diff options
Diffstat (limited to 'compiler/rustc_codegen_cranelift/src/num.rs')
| -rw-r--r-- | compiler/rustc_codegen_cranelift/src/num.rs | 463 |
1 files changed, 463 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_cranelift/src/num.rs b/compiler/rustc_codegen_cranelift/src/num.rs new file mode 100644 index 00000000000..ecbab408ded --- /dev/null +++ b/compiler/rustc_codegen_cranelift/src/num.rs @@ -0,0 +1,463 @@ +//! Various operations on integer and floating-point numbers + +use crate::prelude::*; + +pub(crate) fn bin_op_to_intcc(bin_op: BinOp, signed: bool) -> Option<IntCC> { + use BinOp::*; + use IntCC::*; + Some(match bin_op { + Eq => Equal, + Lt => { + if signed { + SignedLessThan + } else { + UnsignedLessThan + } + } + Le => { + if signed { + SignedLessThanOrEqual + } else { + UnsignedLessThanOrEqual + } + } + Ne => NotEqual, + Ge => { + if signed { + SignedGreaterThanOrEqual + } else { + UnsignedGreaterThanOrEqual + } + } + Gt => { + if signed { + SignedGreaterThan + } else { + UnsignedGreaterThan + } + } + _ => return None, + }) +} + +fn codegen_compare_bin_op<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + bin_op: BinOp, + signed: bool, + lhs: Value, + rhs: Value, +) -> CValue<'tcx> { + let intcc = crate::num::bin_op_to_intcc(bin_op, signed).unwrap(); + let val = fx.bcx.ins().icmp(intcc, lhs, rhs); + let val = fx.bcx.ins().bint(types::I8, val); + CValue::by_val(val, fx.layout_of(fx.tcx.types.bool)) +} + +pub(crate) fn codegen_binop<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + bin_op: BinOp, + in_lhs: CValue<'tcx>, + in_rhs: CValue<'tcx>, +) -> CValue<'tcx> { + match bin_op { + BinOp::Eq | BinOp::Lt | BinOp::Le | BinOp::Ne | BinOp::Ge | BinOp::Gt => { + match in_lhs.layout().ty.kind() { + ty::Bool | ty::Uint(_) | ty::Int(_) | ty::Char => { + let signed = type_sign(in_lhs.layout().ty); + let lhs = in_lhs.load_scalar(fx); + let rhs = in_rhs.load_scalar(fx); + + return codegen_compare_bin_op(fx, bin_op, signed, lhs, rhs); + } + _ => {} + } + } + _ => {} + } + + match in_lhs.layout().ty.kind() { + ty::Bool => crate::num::codegen_bool_binop(fx, bin_op, in_lhs, in_rhs), + ty::Uint(_) | ty::Int(_) => crate::num::codegen_int_binop(fx, bin_op, in_lhs, in_rhs), + ty::Float(_) => crate::num::codegen_float_binop(fx, bin_op, in_lhs, in_rhs), + ty::RawPtr(..) | ty::FnPtr(..) => crate::num::codegen_ptr_binop(fx, bin_op, in_lhs, in_rhs), + _ => unreachable!("{:?}({:?}, {:?})", bin_op, in_lhs.layout().ty, in_rhs.layout().ty), + } +} + +pub(crate) fn codegen_bool_binop<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + bin_op: BinOp, + in_lhs: CValue<'tcx>, + in_rhs: CValue<'tcx>, +) -> CValue<'tcx> { + let lhs = in_lhs.load_scalar(fx); + let rhs = in_rhs.load_scalar(fx); + + let b = fx.bcx.ins(); + let res = match bin_op { + BinOp::BitXor => b.bxor(lhs, rhs), + BinOp::BitAnd => b.band(lhs, rhs), + BinOp::BitOr => b.bor(lhs, rhs), + // Compare binops handles by `codegen_binop`. + _ => unreachable!("{:?}({:?}, {:?})", bin_op, in_lhs, in_rhs), + }; + + CValue::by_val(res, fx.layout_of(fx.tcx.types.bool)) +} + +pub(crate) fn codegen_int_binop<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + bin_op: BinOp, + in_lhs: CValue<'tcx>, + in_rhs: CValue<'tcx>, +) -> CValue<'tcx> { + if bin_op != BinOp::Shl && bin_op != BinOp::Shr { + assert_eq!( + in_lhs.layout().ty, + in_rhs.layout().ty, + "int binop requires lhs and rhs of same type" + ); + } + + if let Some(res) = crate::codegen_i128::maybe_codegen(fx, bin_op, false, in_lhs, in_rhs) { + return res; + } + + let signed = type_sign(in_lhs.layout().ty); + + let lhs = in_lhs.load_scalar(fx); + let rhs = in_rhs.load_scalar(fx); + + let b = fx.bcx.ins(); + let val = match bin_op { + BinOp::Add => b.iadd(lhs, rhs), + BinOp::Sub => b.isub(lhs, rhs), + BinOp::Mul => b.imul(lhs, rhs), + BinOp::Div => { + if signed { + b.sdiv(lhs, rhs) + } else { + b.udiv(lhs, rhs) + } + } + BinOp::Rem => { + if signed { + b.srem(lhs, rhs) + } else { + b.urem(lhs, rhs) + } + } + BinOp::BitXor => b.bxor(lhs, rhs), + BinOp::BitAnd => b.band(lhs, rhs), + BinOp::BitOr => b.bor(lhs, rhs), + BinOp::Shl => b.ishl(lhs, rhs), + BinOp::Shr => { + if signed { + b.sshr(lhs, rhs) + } else { + b.ushr(lhs, rhs) + } + } + // Compare binops handles by `codegen_binop`. + _ => unreachable!("{:?}({:?}, {:?})", bin_op, in_lhs.layout().ty, in_rhs.layout().ty), + }; + + CValue::by_val(val, in_lhs.layout()) +} + +pub(crate) fn codegen_checked_int_binop<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + bin_op: BinOp, + in_lhs: CValue<'tcx>, + in_rhs: CValue<'tcx>, +) -> CValue<'tcx> { + if bin_op != BinOp::Shl && bin_op != BinOp::Shr { + assert_eq!( + in_lhs.layout().ty, + in_rhs.layout().ty, + "checked int binop requires lhs and rhs of same type" + ); + } + + let lhs = in_lhs.load_scalar(fx); + let rhs = in_rhs.load_scalar(fx); + + if let Some(res) = crate::codegen_i128::maybe_codegen(fx, bin_op, true, in_lhs, in_rhs) { + return res; + } + + let signed = type_sign(in_lhs.layout().ty); + + let (res, has_overflow) = match bin_op { + BinOp::Add => { + /*let (val, c_out) = fx.bcx.ins().iadd_cout(lhs, rhs); + (val, c_out)*/ + // FIXME(CraneStation/cranelift#849) legalize iadd_cout for i8 and i16 + let val = fx.bcx.ins().iadd(lhs, rhs); + let has_overflow = if !signed { + fx.bcx.ins().icmp(IntCC::UnsignedLessThan, val, lhs) + } else { + let rhs_is_negative = fx.bcx.ins().icmp_imm(IntCC::SignedLessThan, rhs, 0); + let slt = fx.bcx.ins().icmp(IntCC::SignedLessThan, val, lhs); + fx.bcx.ins().bxor(rhs_is_negative, slt) + }; + (val, has_overflow) + } + BinOp::Sub => { + /*let (val, b_out) = fx.bcx.ins().isub_bout(lhs, rhs); + (val, b_out)*/ + // FIXME(CraneStation/cranelift#849) legalize isub_bout for i8 and i16 + let val = fx.bcx.ins().isub(lhs, rhs); + let has_overflow = if !signed { + fx.bcx.ins().icmp(IntCC::UnsignedGreaterThan, val, lhs) + } else { + let rhs_is_negative = fx.bcx.ins().icmp_imm(IntCC::SignedLessThan, rhs, 0); + let sgt = fx.bcx.ins().icmp(IntCC::SignedGreaterThan, val, lhs); + fx.bcx.ins().bxor(rhs_is_negative, sgt) + }; + (val, has_overflow) + } + BinOp::Mul => { + let ty = fx.bcx.func.dfg.value_type(lhs); + match ty { + types::I8 | types::I16 | types::I32 if !signed => { + let lhs = fx.bcx.ins().uextend(ty.double_width().unwrap(), lhs); + let rhs = fx.bcx.ins().uextend(ty.double_width().unwrap(), rhs); + let val = fx.bcx.ins().imul(lhs, rhs); + let has_overflow = fx.bcx.ins().icmp_imm( + IntCC::UnsignedGreaterThan, + val, + (1 << ty.bits()) - 1, + ); + let val = fx.bcx.ins().ireduce(ty, val); + (val, has_overflow) + } + types::I8 | types::I16 | types::I32 if signed => { + let lhs = fx.bcx.ins().sextend(ty.double_width().unwrap(), lhs); + let rhs = fx.bcx.ins().sextend(ty.double_width().unwrap(), rhs); + let val = fx.bcx.ins().imul(lhs, rhs); + let has_underflow = + fx.bcx.ins().icmp_imm(IntCC::SignedLessThan, val, -(1 << (ty.bits() - 1))); + let has_overflow = fx.bcx.ins().icmp_imm( + IntCC::SignedGreaterThan, + val, + (1 << (ty.bits() - 1)) - 1, + ); + let val = fx.bcx.ins().ireduce(ty, val); + (val, fx.bcx.ins().bor(has_underflow, has_overflow)) + } + types::I64 => { + let val = fx.bcx.ins().imul(lhs, rhs); + let has_overflow = if !signed { + let val_hi = fx.bcx.ins().umulhi(lhs, rhs); + fx.bcx.ins().icmp_imm(IntCC::NotEqual, val_hi, 0) + } else { + // Based on LLVM's instruction sequence for compiling + // a.checked_mul(b).is_some() to riscv64gc: + // mulh a2, a0, a1 + // mul a0, a0, a1 + // srai a0, a0, 63 + // xor a0, a0, a2 + // snez a0, a0 + let val_hi = fx.bcx.ins().smulhi(lhs, rhs); + let val_sign = fx.bcx.ins().sshr_imm(val, i64::from(ty.bits() - 1)); + let xor = fx.bcx.ins().bxor(val_hi, val_sign); + fx.bcx.ins().icmp_imm(IntCC::NotEqual, xor, 0) + }; + (val, has_overflow) + } + types::I128 => { + unreachable!("i128 should have been handled by codegen_i128::maybe_codegen") + } + _ => unreachable!("invalid non-integer type {}", ty), + } + } + BinOp::Shl => { + let val = fx.bcx.ins().ishl(lhs, rhs); + let ty = fx.bcx.func.dfg.value_type(val); + let max_shift = i64::from(ty.bits()) - 1; + let has_overflow = fx.bcx.ins().icmp_imm(IntCC::UnsignedGreaterThan, rhs, max_shift); + (val, has_overflow) + } + BinOp::Shr => { + let val = + if !signed { fx.bcx.ins().ushr(lhs, rhs) } else { fx.bcx.ins().sshr(lhs, rhs) }; + let ty = fx.bcx.func.dfg.value_type(val); + let max_shift = i64::from(ty.bits()) - 1; + let has_overflow = fx.bcx.ins().icmp_imm(IntCC::UnsignedGreaterThan, rhs, max_shift); + (val, has_overflow) + } + _ => bug!("binop {:?} on checked int/uint lhs: {:?} rhs: {:?}", bin_op, in_lhs, in_rhs), + }; + + let has_overflow = fx.bcx.ins().bint(types::I8, has_overflow); + + let out_layout = fx.layout_of(fx.tcx.mk_tup([in_lhs.layout().ty, fx.tcx.types.bool].iter())); + CValue::by_val_pair(res, has_overflow, out_layout) +} + +pub(crate) fn codegen_saturating_int_binop<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + bin_op: BinOp, + lhs: CValue<'tcx>, + rhs: CValue<'tcx>, +) -> CValue<'tcx> { + assert_eq!(lhs.layout().ty, rhs.layout().ty); + + let signed = type_sign(lhs.layout().ty); + let clif_ty = fx.clif_type(lhs.layout().ty).unwrap(); + let (min, max) = type_min_max_value(&mut fx.bcx, clif_ty, signed); + + let checked_res = crate::num::codegen_checked_int_binop(fx, bin_op, lhs, rhs); + let (val, has_overflow) = checked_res.load_scalar_pair(fx); + + let val = match (bin_op, signed) { + (BinOp::Add, false) => fx.bcx.ins().select(has_overflow, max, val), + (BinOp::Sub, false) => fx.bcx.ins().select(has_overflow, min, val), + (BinOp::Add, true) => { + let rhs = rhs.load_scalar(fx); + let rhs_ge_zero = fx.bcx.ins().icmp_imm(IntCC::SignedGreaterThanOrEqual, rhs, 0); + let sat_val = fx.bcx.ins().select(rhs_ge_zero, max, min); + fx.bcx.ins().select(has_overflow, sat_val, val) + } + (BinOp::Sub, true) => { + let rhs = rhs.load_scalar(fx); + let rhs_ge_zero = fx.bcx.ins().icmp_imm(IntCC::SignedGreaterThanOrEqual, rhs, 0); + let sat_val = fx.bcx.ins().select(rhs_ge_zero, min, max); + fx.bcx.ins().select(has_overflow, sat_val, val) + } + _ => unreachable!(), + }; + + CValue::by_val(val, lhs.layout()) +} + +pub(crate) fn codegen_float_binop<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + bin_op: BinOp, + in_lhs: CValue<'tcx>, + in_rhs: CValue<'tcx>, +) -> CValue<'tcx> { + assert_eq!(in_lhs.layout().ty, in_rhs.layout().ty); + + let lhs = in_lhs.load_scalar(fx); + let rhs = in_rhs.load_scalar(fx); + + let b = fx.bcx.ins(); + let res = match bin_op { + BinOp::Add => b.fadd(lhs, rhs), + BinOp::Sub => b.fsub(lhs, rhs), + BinOp::Mul => b.fmul(lhs, rhs), + BinOp::Div => b.fdiv(lhs, rhs), + BinOp::Rem => { + let name = match in_lhs.layout().ty.kind() { + ty::Float(FloatTy::F32) => "fmodf", + ty::Float(FloatTy::F64) => "fmod", + _ => bug!(), + }; + return fx.easy_call(name, &[in_lhs, in_rhs], in_lhs.layout().ty); + } + BinOp::Eq | BinOp::Lt | BinOp::Le | BinOp::Ne | BinOp::Ge | BinOp::Gt => { + let fltcc = match bin_op { + BinOp::Eq => FloatCC::Equal, + BinOp::Lt => FloatCC::LessThan, + BinOp::Le => FloatCC::LessThanOrEqual, + BinOp::Ne => FloatCC::NotEqual, + BinOp::Ge => FloatCC::GreaterThanOrEqual, + BinOp::Gt => FloatCC::GreaterThan, + _ => unreachable!(), + }; + let val = fx.bcx.ins().fcmp(fltcc, lhs, rhs); + let val = fx.bcx.ins().bint(types::I8, val); + return CValue::by_val(val, fx.layout_of(fx.tcx.types.bool)); + } + _ => unreachable!("{:?}({:?}, {:?})", bin_op, in_lhs, in_rhs), + }; + + CValue::by_val(res, in_lhs.layout()) +} + +pub(crate) fn codegen_ptr_binop<'tcx>( + fx: &mut FunctionCx<'_, '_, 'tcx>, + bin_op: BinOp, + in_lhs: CValue<'tcx>, + in_rhs: CValue<'tcx>, +) -> CValue<'tcx> { + let is_thin_ptr = in_lhs + .layout() + .ty + .builtin_deref(true) + .map(|TypeAndMut { ty, mutbl: _ }| !has_ptr_meta(fx.tcx, ty)) + .unwrap_or(true); + + if is_thin_ptr { + match bin_op { + BinOp::Eq | BinOp::Lt | BinOp::Le | BinOp::Ne | BinOp::Ge | BinOp::Gt => { + let lhs = in_lhs.load_scalar(fx); + let rhs = in_rhs.load_scalar(fx); + + codegen_compare_bin_op(fx, bin_op, false, lhs, rhs) + } + BinOp::Offset => { + let pointee_ty = in_lhs.layout().ty.builtin_deref(true).unwrap().ty; + let (base, offset) = (in_lhs, in_rhs.load_scalar(fx)); + let pointee_size = fx.layout_of(pointee_ty).size.bytes(); + let ptr_diff = fx.bcx.ins().imul_imm(offset, pointee_size as i64); + let base_val = base.load_scalar(fx); + let res = fx.bcx.ins().iadd(base_val, ptr_diff); + CValue::by_val(res, base.layout()) + } + _ => unreachable!("{:?}({:?}, {:?})", bin_op, in_lhs, in_rhs), + } + } else { + let (lhs_ptr, lhs_extra) = in_lhs.load_scalar_pair(fx); + let (rhs_ptr, rhs_extra) = in_rhs.load_scalar_pair(fx); + + let res = match bin_op { + BinOp::Eq => { + let ptr_eq = fx.bcx.ins().icmp(IntCC::Equal, lhs_ptr, rhs_ptr); + let extra_eq = fx.bcx.ins().icmp(IntCC::Equal, lhs_extra, rhs_extra); + fx.bcx.ins().band(ptr_eq, extra_eq) + } + BinOp::Ne => { + let ptr_ne = fx.bcx.ins().icmp(IntCC::NotEqual, lhs_ptr, rhs_ptr); + let extra_ne = fx.bcx.ins().icmp(IntCC::NotEqual, lhs_extra, rhs_extra); + fx.bcx.ins().bor(ptr_ne, extra_ne) + } + BinOp::Lt | BinOp::Le | BinOp::Ge | BinOp::Gt => { + let ptr_eq = fx.bcx.ins().icmp(IntCC::Equal, lhs_ptr, rhs_ptr); + + let ptr_cmp = + fx.bcx.ins().icmp(bin_op_to_intcc(bin_op, false).unwrap(), lhs_ptr, rhs_ptr); + let extra_cmp = fx.bcx.ins().icmp( + bin_op_to_intcc(bin_op, false).unwrap(), + lhs_extra, + rhs_extra, + ); + + fx.bcx.ins().select(ptr_eq, extra_cmp, ptr_cmp) + } + _ => panic!("bin_op {:?} on ptr", bin_op), + }; + + CValue::by_val(fx.bcx.ins().bint(types::I8, res), fx.layout_of(fx.tcx.types.bool)) + } +} + +// In Rust floating point min and max don't propagate NaN. In Cranelift they do however. +// For this reason it is necessary to use `a.is_nan() ? b : (a >= b ? b : a)` for `minnumf*` +// and `a.is_nan() ? b : (a <= b ? b : a)` for `maxnumf*`. NaN checks are done by comparing +// a float against itself. Only in case of NaN is it not equal to itself. +pub(crate) fn codegen_float_min(fx: &mut FunctionCx<'_, '_, '_>, a: Value, b: Value) -> Value { + let a_is_nan = fx.bcx.ins().fcmp(FloatCC::NotEqual, a, a); + let a_ge_b = fx.bcx.ins().fcmp(FloatCC::GreaterThanOrEqual, a, b); + let temp = fx.bcx.ins().select(a_ge_b, b, a); + fx.bcx.ins().select(a_is_nan, b, temp) +} + +pub(crate) fn codegen_float_max(fx: &mut FunctionCx<'_, '_, '_>, a: Value, b: Value) -> Value { + let a_is_nan = fx.bcx.ins().fcmp(FloatCC::NotEqual, a, a); + let a_le_b = fx.bcx.ins().fcmp(FloatCC::LessThanOrEqual, a, b); + let temp = fx.bcx.ins().select(a_le_b, b, a); + fx.bcx.ins().select(a_is_nan, b, temp) +} |