116 lines
4.5 KiB
Rust
116 lines
4.5 KiB
Rust
use rustc::ty::{self, Ty};
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use syntax::ast::{FloatTy, IntTy, UintTy};
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use error::{EvalResult, EvalError};
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use eval_context::EvalContext;
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use value::PrimVal;
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impl<'a, 'tcx> EvalContext<'a, 'tcx> {
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pub(super) fn cast_primval(
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&self,
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val: PrimVal,
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src_ty: Ty<'tcx>,
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dest_ty: Ty<'tcx>
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) -> EvalResult<'tcx, PrimVal> {
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let kind = self.ty_to_primval_kind(src_ty)?;
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use value::PrimValKind::*;
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match kind {
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F32 => self.cast_float(val.to_f32()? as f64, dest_ty),
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F64 => self.cast_float(val.to_f64()?, dest_ty),
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I8 | I16 | I32 | I64 | I128 => {
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if val.is_ptr() {
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self.cast_ptr(val, dest_ty)
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} else {
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self.cast_signed_int(val.to_i128()?, dest_ty)
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}
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},
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Bool | Char | U8 | U16 | U32 | U64 | U128 => {
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if val.is_ptr() {
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self.cast_ptr(val, dest_ty)
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} else {
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self.cast_int(val.to_u128()?, dest_ty, false)
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}
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},
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FnPtr | Ptr => self.cast_ptr(val, dest_ty),
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}
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}
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fn cast_signed_int(&self, val: i128, ty: ty::Ty<'tcx>) -> EvalResult<'tcx, PrimVal> {
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self.cast_int(val as u128, ty, val < 0)
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}
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fn cast_int(&self, v: u128, ty: ty::Ty<'tcx>, negative: bool) -> EvalResult<'tcx, PrimVal> {
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use rustc::ty::TypeVariants::*;
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match ty.sty {
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// Casts to bool are not permitted by rustc, no need to handle them here.
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TyInt(IntTy::I8) => Ok(PrimVal::Bytes(v as i128 as i8 as u128)),
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TyInt(IntTy::I16) => Ok(PrimVal::Bytes(v as i128 as i16 as u128)),
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TyInt(IntTy::I32) => Ok(PrimVal::Bytes(v as i128 as i32 as u128)),
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TyInt(IntTy::I64) => Ok(PrimVal::Bytes(v as i128 as i64 as u128)),
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TyInt(IntTy::I128) => Ok(PrimVal::Bytes(v as u128)),
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TyUint(UintTy::U8) => Ok(PrimVal::Bytes(v as u8 as u128)),
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TyUint(UintTy::U16) => Ok(PrimVal::Bytes(v as u16 as u128)),
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TyUint(UintTy::U32) => Ok(PrimVal::Bytes(v as u32 as u128)),
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TyUint(UintTy::U64) => Ok(PrimVal::Bytes(v as u64 as u128)),
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TyUint(UintTy::U128) => Ok(PrimVal::Bytes(v)),
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TyInt(IntTy::Is) => {
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let int_ty = self.tcx.sess.target.int_type;
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let ty = self.tcx.mk_mach_int(int_ty);
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self.cast_int(v, ty, negative)
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}
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TyUint(UintTy::Us) => {
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let uint_ty = self.tcx.sess.target.uint_type;
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let ty = self.tcx.mk_mach_uint(uint_ty);
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self.cast_int(v, ty, negative)
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}
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TyFloat(FloatTy::F64) if negative => Ok(PrimVal::from_f64(v as i128 as f64)),
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TyFloat(FloatTy::F64) => Ok(PrimVal::from_f64(v as f64)),
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TyFloat(FloatTy::F32) if negative => Ok(PrimVal::from_f32(v as i128 as f32)),
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TyFloat(FloatTy::F32) => Ok(PrimVal::from_f32(v as f32)),
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TyChar if v as u8 as u128 == v => Ok(PrimVal::Bytes(v)),
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TyChar => Err(EvalError::InvalidChar(v)),
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// No alignment check needed for raw pointers
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TyRawPtr(_) => Ok(PrimVal::Bytes(v % (1 << self.memory.pointer_size()))),
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_ => Err(EvalError::Unimplemented(format!("int to {:?} cast", ty))),
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}
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}
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fn cast_float(&self, val: f64, ty: Ty<'tcx>) -> EvalResult<'tcx, PrimVal> {
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use rustc::ty::TypeVariants::*;
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match ty.sty {
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// Casting negative floats to unsigned integers yields zero.
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TyUint(_) if val < 0.0 => self.cast_int(0, ty, false),
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TyInt(_) if val < 0.0 => self.cast_int(val as i128 as u128, ty, true),
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TyInt(_) | ty::TyUint(_) => self.cast_int(val as u128, ty, false),
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TyFloat(FloatTy::F64) => Ok(PrimVal::from_f64(val)),
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TyFloat(FloatTy::F32) => Ok(PrimVal::from_f32(val as f32)),
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_ => Err(EvalError::Unimplemented(format!("float to {:?} cast", ty))),
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}
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}
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fn cast_ptr(&self, ptr: PrimVal, ty: Ty<'tcx>) -> EvalResult<'tcx, PrimVal> {
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use rustc::ty::TypeVariants::*;
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match ty.sty {
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// Casting to a reference or fn pointer is not permitted by rustc, no need to support it here.
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TyRawPtr(_) | TyInt(IntTy::Is) | TyUint(UintTy::Us) =>
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Ok(ptr),
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TyInt(_) | TyUint(_) => Err(EvalError::ReadPointerAsBytes),
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_ => Err(EvalError::Unimplemented(format!("ptr to {:?} cast", ty))),
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}
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}
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}
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