diff options
Diffstat (limited to 'compiler/rustc_codegen_ssa/src/mir/constant.rs')
-rw-r--r-- | compiler/rustc_codegen_ssa/src/mir/constant.rs | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/compiler/rustc_codegen_ssa/src/mir/constant.rs b/compiler/rustc_codegen_ssa/src/mir/constant.rs new file mode 100644 index 000000000..9a995fbf6 --- /dev/null +++ b/compiler/rustc_codegen_ssa/src/mir/constant.rs @@ -0,0 +1,90 @@ +use crate::mir::operand::OperandRef; +use crate::traits::*; +use rustc_middle::mir; +use rustc_middle::mir::interpret::{ConstValue, ErrorHandled}; +use rustc_middle::ty::layout::HasTyCtxt; +use rustc_middle::ty::{self, Ty}; +use rustc_span::source_map::Span; +use rustc_target::abi::Abi; + +use super::FunctionCx; + +impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> { + pub fn eval_mir_constant_to_operand( + &self, + bx: &mut Bx, + constant: &mir::Constant<'tcx>, + ) -> Result<OperandRef<'tcx, Bx::Value>, ErrorHandled> { + let val = self.eval_mir_constant(constant)?; + let ty = self.monomorphize(constant.ty()); + Ok(OperandRef::from_const(bx, val, ty)) + } + + pub fn eval_mir_constant( + &self, + constant: &mir::Constant<'tcx>, + ) -> Result<ConstValue<'tcx>, ErrorHandled> { + let ct = self.monomorphize(constant.literal); + let ct = match ct { + mir::ConstantKind::Ty(ct) => ct, + mir::ConstantKind::Val(val, _) => return Ok(val), + }; + match ct.kind() { + ty::ConstKind::Unevaluated(ct) => self + .cx + .tcx() + .const_eval_resolve(ty::ParamEnv::reveal_all(), ct, None) + .map_err(|err| { + self.cx.tcx().sess.span_err(constant.span, "erroneous constant encountered"); + err + }), + ty::ConstKind::Value(val) => Ok(self.cx.tcx().valtree_to_const_val((ct.ty(), val))), + err => span_bug!( + constant.span, + "encountered bad ConstKind after monomorphizing: {:?}", + err + ), + } + } + + /// process constant containing SIMD shuffle indices + pub fn simd_shuffle_indices( + &mut self, + bx: &Bx, + span: Span, + ty: Ty<'tcx>, + constant: Result<ConstValue<'tcx>, ErrorHandled>, + ) -> (Bx::Value, Ty<'tcx>) { + constant + .map(|val| { + let field_ty = ty.builtin_index().unwrap(); + let c = mir::ConstantKind::from_value(val, ty); + let values: Vec<_> = bx + .tcx() + .destructure_mir_constant(ty::ParamEnv::reveal_all(), c) + .fields + .iter() + .map(|field| { + if let Some(prim) = field.try_to_scalar() { + let layout = bx.layout_of(field_ty); + let Abi::Scalar(scalar) = layout.abi else { + bug!("from_const: invalid ByVal layout: {:#?}", layout); + }; + bx.scalar_to_backend(prim, scalar, bx.immediate_backend_type(layout)) + } else { + bug!("simd shuffle field {:?}", field) + } + }) + .collect(); + let llval = bx.const_struct(&values, false); + (llval, c.ty()) + }) + .unwrap_or_else(|_| { + bx.tcx().sess.span_err(span, "could not evaluate shuffle_indices at compile time"); + // We've errored, so we don't have to produce working code. + let ty = self.monomorphize(ty); + let llty = bx.backend_type(bx.layout_of(ty)); + (bx.const_undef(llty), ty) + }) + } +} |