use llvm::{self, ValueRef};
use rustc::middle::const_val::{ConstEvalErr, ConstVal, ErrKind};
use rustc_const_math::ConstInt::*;
-use rustc_const_math::{ConstInt, ConstMathErr};
+use rustc_const_math::{ConstInt, ConstMathErr, MAX_F32_PLUS_HALF_ULP};
use rustc::hir::def_id::DefId;
use rustc::infer::TransNormalize;
use rustc::traits;
use rustc::ty::layout::{self, LayoutTyper};
use rustc::ty::cast::{CastTy, IntTy};
use rustc::ty::subst::{Kind, Substs, Subst};
+use rustc_apfloat::{ieee, Float, Status};
use rustc_data_structures::indexed_vec::{Idx, IndexVec};
use {adt, base, machine};
use abi::{self, Abi};
.projection_ty(tcx, &projection.elem);
let base = tr_base.to_const(span);
let projected_ty = self.monomorphize(&projected_ty).to_ty(tcx);
- let is_sized = self.ccx.shared().type_is_sized(projected_ty);
+ let has_metadata = self.ccx.shared().type_has_metadata(projected_ty);
let (projected, llextra) = match projection.elem {
mir::ProjectionElem::Deref => {
- let (base, extra) = if is_sized {
+ let (base, extra) = if !has_metadata {
(base.llval, ptr::null_mut())
} else {
base.get_fat_ptr()
mir::ProjectionElem::Field(ref field, _) => {
let llprojected = adt::const_get_field(self.ccx, tr_base.ty, base.llval,
field.index());
- let llextra = if is_sized {
+ let llextra = if !has_metadata {
ptr::null_mut()
} else {
tr_base.llextra
llvm::LLVMConstIntCast(llval, ll_t_out.to_ref(), s)
}
(CastTy::Int(_), CastTy::Float) => {
- if signed {
- llvm::LLVMConstSIToFP(llval, ll_t_out.to_ref())
- } else {
- llvm::LLVMConstUIToFP(llval, ll_t_out.to_ref())
- }
+ cast_const_int_to_float(self.ccx, llval, signed, ll_t_out)
}
(CastTy::Float, CastTy::Float) => {
llvm::LLVMConstFPCast(llval, ll_t_out.to_ref())
}
(CastTy::Float, CastTy::Int(IntTy::I)) => {
- llvm::LLVMConstFPToSI(llval, ll_t_out.to_ref())
+ cast_const_float_to_int(self.ccx, &operand,
+ true, ll_t_out, span)
}
(CastTy::Float, CastTy::Int(_)) => {
- llvm::LLVMConstFPToUI(llval, ll_t_out.to_ref())
+ cast_const_float_to_int(self.ccx, &operand,
+ false, ll_t_out, span)
}
(CastTy::Ptr(_), CastTy::Ptr(_)) |
(CastTy::FnPtr, CastTy::Ptr(_)) |
}
}
+unsafe fn cast_const_float_to_int(ccx: &CrateContext,
+ operand: &Const,
+ signed: bool,
+ int_ty: Type,
+ span: Span) -> ValueRef {
+ let llval = operand.llval;
+ let float_bits = match operand.ty.sty {
+ ty::TyFloat(fty) => fty.bit_width(),
+ _ => bug!("cast_const_float_to_int: operand not a float"),
+ };
+ // Note: this breaks if llval is a complex constant expression rather than a simple constant.
+ // One way that might happen would be if addresses could be turned into integers in constant
+ // expressions, but that doesn't appear to be possible?
+ // In any case, an ICE is better than producing undef.
+ let llval_bits = consts::bitcast(llval, Type::ix(ccx, float_bits as u64));
+ let bits = const_to_opt_u128(llval_bits, false).unwrap_or_else(|| {
+ panic!("could not get bits of constant float {:?}",
+ Value(llval));
+ });
+ let int_width = int_ty.int_width() as usize;
+ // Try to convert, but report an error for overflow and NaN. This matches HIR const eval.
+ let cast_result = match float_bits {
+ 32 if signed => ieee::Single::from_bits(bits).to_i128(int_width).map(|v| v as u128),
+ 64 if signed => ieee::Double::from_bits(bits).to_i128(int_width).map(|v| v as u128),
+ 32 => ieee::Single::from_bits(bits).to_u128(int_width),
+ 64 => ieee::Double::from_bits(bits).to_u128(int_width),
+ n => bug!("unsupported float width {}", n),
+ };
+ if cast_result.status.contains(Status::INVALID_OP) {
+ let err = ConstEvalErr { span: span, kind: ErrKind::CannotCast };
+ err.report(ccx.tcx(), span, "expression");
+ }
+ C_big_integral(int_ty, cast_result.value)
+}
+
+unsafe fn cast_const_int_to_float(ccx: &CrateContext,
+ llval: ValueRef,
+ signed: bool,
+ float_ty: Type) -> ValueRef {
+ // Note: this breaks if llval is a complex constant expression rather than a simple constant.
+ // One way that might happen would be if addresses could be turned into integers in constant
+ // expressions, but that doesn't appear to be possible?
+ // In any case, an ICE is better than producing undef.
+ let value = const_to_opt_u128(llval, signed).unwrap_or_else(|| {
+ panic!("could not get z128 value of constant integer {:?}",
+ Value(llval));
+ });
+ if signed {
+ llvm::LLVMConstSIToFP(llval, float_ty.to_ref())
+ } else if float_ty.float_width() == 32 && value >= MAX_F32_PLUS_HALF_ULP {
+ // We're casting to f32 and the value is > f32::MAX + 0.5 ULP -> round up to infinity.
+ let infinity_bits = C_u32(ccx, ieee::Single::INFINITY.to_bits() as u32);
+ consts::bitcast(infinity_bits, float_ty)
+ } else {
+ llvm::LLVMConstUIToFP(llval, float_ty.to_ref())
+ }
+}
+
impl<'a, 'tcx> MirContext<'a, 'tcx> {
pub fn trans_constant(&mut self,
bcx: &Builder<'a, 'tcx>,
projects / rustc.git / blobdiff