bjoernager/rust
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dont make lit_to_mir_constant a query

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This commit is contained in:
b-naber 2022-04-08 11:56:21 +02:00
parent c3491378e3
commit 3be987e076
4 changed files with 56 additions and 57 deletions
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57
compiler/rustc_mir_build/src/build/expr/as_constant.rs
View file

@ -1,12 +1,16 @@
//! See docs in build/expr/mod.rs
use crate::build::Builder;
use crate::thir::constant::parse_float;
use rustc_ast as ast;
use rustc_hir::def_id::DefId;
use rustc_middle::mir::interpret::Allocation;
use rustc_middle::mir::interpret::{ConstValue, LitToConstError, LitToConstInput, Scalar};
use rustc_middle::mir::*;
use rustc_middle::thir::*;
use rustc_middle::ty::subst::SubstsRef;
use rustc_middle::ty::{self, CanonicalUserTypeAnnotation, Ty, TyCtxt};
use rustc_target::abi::Size;
impl<'a, 'tcx> Builder<'a, 'tcx> {
/// Compile `expr`, yielding a compile-time constant. Assumes that
@ -27,7 +31,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
}
ExprKind::Literal { lit, neg } => {
let literal =
match tcx.lit_to_mir_constant(LitToConstInput { lit: &lit.node, ty, neg }) {
match lit_to_mir_constant(tcx, LitToConstInput { lit: &lit.node, ty, neg }) {
Ok(c) => c,
Err(LitToConstError::Reported) => ConstantKind::Ty(tcx.const_error(ty)),
Err(LitToConstError::TypeError) => {
@ -84,3 +88,54 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
}
}
}
#[instrument(skip(tcx, lit_input))]
fn lit_to_mir_constant<'tcx>(
tcx: TyCtxt<'tcx>,
lit_input: LitToConstInput<'tcx>,
) -> Result<ConstantKind<'tcx>, LitToConstError> {
let LitToConstInput { lit, ty, neg } = lit_input;
let trunc = |n| {
let param_ty = ty::ParamEnv::reveal_all().and(ty);
let width = tcx.layout_of(param_ty).map_err(|_| LitToConstError::Reported)?.size;
trace!("trunc {} with size {} and shift {}", n, width.bits(), 128 - width.bits());
let result = width.truncate(n);
trace!("trunc result: {}", result);
Ok(ConstValue::Scalar(Scalar::from_uint(result, width)))
};
let value = match (lit, &ty.kind()) {
(ast::LitKind::Str(s, _), ty::Ref(_, inner_ty, _)) if inner_ty.is_str() => {
let s = s.as_str();
let allocation = Allocation::from_bytes_byte_aligned_immutable(s.as_bytes());
let allocation = tcx.intern_const_alloc(allocation);
ConstValue::Slice { data: allocation, start: 0, end: s.len() }
}
(ast::LitKind::ByteStr(data), ty::Ref(_, inner_ty, _))
if matches!(inner_ty.kind(), ty::Slice(_)) =>
{
let allocation = Allocation::from_bytes_byte_aligned_immutable(data as &[u8]);
let allocation = tcx.intern_const_alloc(allocation);
ConstValue::Slice { data: allocation, start: 0, end: data.len() }
}
(ast::LitKind::ByteStr(data), ty::Ref(_, inner_ty, _)) if inner_ty.is_array() => {
let id = tcx.allocate_bytes(data);
ConstValue::Scalar(Scalar::from_pointer(id.into(), &tcx))
}
(ast::LitKind::Byte(n), ty::Uint(ty::UintTy::U8)) => {
ConstValue::Scalar(Scalar::from_uint(*n, Size::from_bytes(1)))
}
(ast::LitKind::Int(n, _), ty::Uint(_)) | (ast::LitKind::Int(n, _), ty::Int(_)) => {
trunc(if neg { (*n as i128).overflowing_neg().0 as u128 } else { *n })?
}
(ast::LitKind::Float(n, _), ty::Float(fty)) => {
parse_float(*n, *fty, neg).ok_or(LitToConstError::Reported)?
}
(ast::LitKind::Bool(b), ty::Bool) => ConstValue::Scalar(Scalar::from_bool(*b)),
(ast::LitKind::Char(c), ty::Char) => ConstValue::Scalar(Scalar::from_char(*c)),
(ast::LitKind::Err(_), _) => return Err(LitToConstError::Reported),
_ => return Err(LitToConstError::TypeError),
};
Ok(ConstantKind::Val(value, ty))
}

1
compiler/rustc_mir_build/src/lib.rs
View file

@ -27,7 +27,6 @@ use rustc_middle::ty::query::Providers;
pub fn provide(providers: &mut Providers) {
providers.check_match = thir::pattern::check_match;
providers.lit_to_const = thir::constant::lit_to_const;
providers.lit_to_mir_constant = thir::constant::lit_to_mir_constant;
providers.mir_built = build::mir_built;
providers.thir_check_unsafety = check_unsafety::thir_check_unsafety;
providers.thir_check_unsafety_for_const_arg = check_unsafety::thir_check_unsafety_for_const_arg;

51
compiler/rustc_mir_build/src/thir/constant.rs
View file

@ -3,7 +3,6 @@ use rustc_ast as ast;
use rustc_middle::mir::interpret::{
Allocation, ConstValue, LitToConstError, LitToConstInput, Scalar,
};
use rustc_middle::mir::ConstantKind;
use rustc_middle::ty::{self, ParamEnv, TyCtxt};
use rustc_span::symbol::Symbol;
use rustc_target::abi::Size;
@ -59,56 +58,6 @@ crate fn lit_to_const<'tcx>(
Ok(ty::Const::from_value(tcx, lit, ty))
}
crate fn lit_to_mir_constant<'tcx>(
tcx: TyCtxt<'tcx>,
lit_input: LitToConstInput<'tcx>,
) -> Result<ConstantKind<'tcx>, LitToConstError> {
let LitToConstInput { lit, ty, neg } = lit_input;
let trunc = |n| {
let param_ty = ty::ParamEnv::reveal_all().and(ty);
let width = tcx.layout_of(param_ty).map_err(|_| LitToConstError::Reported)?.size;
trace!("trunc {} with size {} and shift {}", n, width.bits(), 128 - width.bits());
let result = width.truncate(n);
trace!("trunc result: {}", result);
Ok(ConstValue::Scalar(Scalar::from_uint(result, width)))
};
let value = match (lit, &ty.kind()) {
(ast::LitKind::Str(s, _), ty::Ref(_, inner_ty, _)) if inner_ty.is_str() => {
let s = s.as_str();
let allocation = Allocation::from_bytes_byte_aligned_immutable(s.as_bytes());
let allocation = tcx.intern_const_alloc(allocation);
ConstValue::Slice { data: allocation, start: 0, end: s.len() }
}
(ast::LitKind::ByteStr(data), ty::Ref(_, inner_ty, _))
if matches!(inner_ty.kind(), ty::Slice(_)) =>
{
let allocation = Allocation::from_bytes_byte_aligned_immutable(data as &[u8]);
let allocation = tcx.intern_const_alloc(allocation);
ConstValue::Slice { data: allocation, start: 0, end: data.len() }
}
(ast::LitKind::ByteStr(data), ty::Ref(_, inner_ty, _)) if inner_ty.is_array() => {
let id = tcx.allocate_bytes(data);
ConstValue::Scalar(Scalar::from_pointer(id.into(), &tcx))
}
(ast::LitKind::Byte(n), ty::Uint(ty::UintTy::U8)) => {
ConstValue::Scalar(Scalar::from_uint(*n, Size::from_bytes(1)))
}
(ast::LitKind::Int(n, _), ty::Uint(_)) | (ast::LitKind::Int(n, _), ty::Int(_)) => {
trunc(if neg { (*n as i128).overflowing_neg().0 as u128 } else { *n })?
}
(ast::LitKind::Float(n, _), ty::Float(fty)) => {
parse_float(*n, *fty, neg).ok_or(LitToConstError::Reported)?
}
(ast::LitKind::Bool(b), ty::Bool) => ConstValue::Scalar(Scalar::from_bool(*b)),
(ast::LitKind::Char(c), ty::Char) => ConstValue::Scalar(Scalar::from_char(*c)),
(ast::LitKind::Err(_), _) => return Err(LitToConstError::Reported),
_ => return Err(LitToConstError::TypeError),
};
Ok(ConstantKind::Val(value, ty))
}
// FIXME move this to rustc_mir_build::build
pub(crate) fn parse_float<'tcx>(
num: Symbol,