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Stop using the const_eval query for initializers of statics

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As a side effect, we now represent most promoteds as `ConstValue::Scalar` again. This is useful because all implict promoteds are just references anyway and most explicit promoteds are numeric arguments to `asm!` or SIMD instructions.
This commit is contained in:
Oliver Scherer 2020-07-31 13:27:54 +02:00
parent 083f1d7a37
commit 2d7ac728e4
17 changed files with 53 additions and 108 deletions
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26
compiler/rustc_codegen_ssa/src/mir/block.rs
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@ -13,7 +13,7 @@ use rustc_ast as ast;
use rustc_hir::lang_items::LangItem;
use rustc_index::vec::Idx;
use rustc_middle::mir;
use rustc_middle::mir::interpret::{AllocId, ConstValue, Pointer, Scalar};
use rustc_middle::mir::interpret::ConstValue;
use rustc_middle::mir::AssertKind;
use rustc_middle::ty::layout::{FnAbiExt, HasTyCtxt};
use rustc_middle::ty::print::with_no_trimmed_paths;
@ -867,24 +867,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
let ty = constant.literal.ty;
let size = bx.layout_of(ty).size;
let scalar = match const_value {
// Promoted constants are evaluated into a ByRef instead of a Scalar,
// but we want the scalar value here.
ConstValue::ByRef { alloc, offset } => {
let ptr = Pointer::new(AllocId(0), offset);
alloc
.read_scalar(&bx, ptr, size)
.and_then(|s| s.check_init())
.unwrap_or_else(|e| {
bx.tcx().sess.span_err(
span,
&format!("Could not evaluate asm const: {}", e),
);
// We are erroring out, just emit a dummy constant.
Scalar::from_u64(0)
})
}
_ => span_bug!(span, "expected ByRef for promoted asm const"),
ConstValue::Scalar(s) => s,
_ => span_bug!(
span,
"expected Scalar for promoted asm const, but got {:#?}",
const_value
),
};
let value = scalar.assert_bits(size);
let string = match ty.kind() {