From a992defc8b0d7937d0422003984b7b5d3e5f472e Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Thu, 5 Oct 2023 09:39:33 +0000
Subject: [PATCH 1/3] Remove mir::Const::from_anon_const
---
compiler/rustc_middle/src/mir/consts.rs | 102 +------------------
compiler/rustc_middle/src/ty/consts.rs | 4 +
compiler/rustc_mir_build/src/thir/cx/expr.rs | 26 ++++-
3 files changed, 29 insertions(+), 103 deletions(-)
diff --git a/compiler/rustc_middle/src/mir/consts.rs b/compiler/rustc_middle/src/mir/consts.rs
index 84a9ab4013be6..fa7fa8e8c74d2 100644
--- a/compiler/rustc_middle/src/mir/consts.rs
+++ b/compiler/rustc_middle/src/mir/consts.rs
@@ -1,17 +1,16 @@
use std::fmt::{self, Debug, Display, Formatter};
use rustc_hir;
-use rustc_hir::def_id::{DefId, LocalDefId};
-use rustc_hir::{self as hir};
+use rustc_hir::def_id::DefId;
use rustc_session::RemapFileNameExt;
use rustc_span::Span;
use rustc_target::abi::{HasDataLayout, Size};
use crate::mir::interpret::{alloc_range, AllocId, ConstAllocation, ErrorHandled, Scalar};
use crate::mir::{pretty_print_const_value, Promoted};
+use crate::ty::GenericArgsRef;
use crate::ty::ScalarInt;
-use crate::ty::{self, print::pretty_print_const, List, Ty, TyCtxt};
-use crate::ty::{GenericArgs, GenericArgsRef};
+use crate::ty::{self, print::pretty_print_const, Ty, TyCtxt};
///////////////////////////////////////////////////////////////////////////
/// Evaluated Constants
@@ -399,101 +398,6 @@ impl<'tcx> Const<'tcx> {
Self::Val(val, ty)
}
- /// Literals are converted to `Const::Val`, const generic parameters are eagerly
- /// converted to a constant, everything else becomes `Unevaluated`.
- #[instrument(skip(tcx), level = "debug", ret)]
- pub fn from_anon_const(
- tcx: TyCtxt<'tcx>,
- def: LocalDefId,
- param_env: ty::ParamEnv<'tcx>,
- ) -> Self {
- let body_id = match tcx.hir().get_by_def_id(def) {
- hir::Node::AnonConst(ac) => ac.body,
- _ => {
- span_bug!(tcx.def_span(def), "from_anon_const can only process anonymous constants")
- }
- };
-
- let expr = &tcx.hir().body(body_id).value;
- debug!(?expr);
-
- // Unwrap a block, so that e.g. `{ P }` is recognised as a parameter. Const arguments
- // currently have to be wrapped in curly brackets, so it's necessary to special-case.
- let expr = match &expr.kind {
- hir::ExprKind::Block(block, _) if block.stmts.is_empty() && block.expr.is_some() => {
- block.expr.as_ref().unwrap()
- }
- _ => expr,
- };
- debug!("expr.kind: {:?}", expr.kind);
-
- let ty = tcx.type_of(def).instantiate_identity();
- debug!(?ty);
-
- // FIXME(const_generics): We currently have to special case parameters because `min_const_generics`
- // does not provide the parents generics to anonymous constants. We still allow generic const
- // parameters by themselves however, e.g. `N`. These constants would cause an ICE if we were to
- // ever try to substitute the generic parameters in their bodies.
- //
- // While this doesn't happen as these constants are always used as `ty::ConstKind::Param`, it does
- // cause issues if we were to remove that special-case and try to evaluate the constant instead.
- use hir::{def::DefKind::ConstParam, def::Res, ExprKind, Path, QPath};
- match expr.kind {
- ExprKind::Path(QPath::Resolved(_, &Path { res: Res::Def(ConstParam, def_id), .. })) => {
- // Find the name and index of the const parameter by indexing the generics of
- // the parent item and construct a `ParamConst`.
- let item_def_id = tcx.parent(def_id);
- let generics = tcx.generics_of(item_def_id);
- let index = generics.param_def_id_to_index[&def_id];
- let name = tcx.item_name(def_id);
- let ty_const = ty::Const::new_param(tcx, ty::ParamConst::new(index, name), ty);
- debug!(?ty_const);
-
- return Self::Ty(ty_const);
- }
- _ => {}
- }
-
- let hir_id = tcx.hir().local_def_id_to_hir_id(def);
- let parent_args = if let Some(parent_hir_id) = tcx.hir().opt_parent_id(hir_id)
- && let Some(parent_did) = parent_hir_id.as_owner()
- {
- GenericArgs::identity_for_item(tcx, parent_did)
- } else {
- List::empty()
- };
- debug!(?parent_args);
-
- let did = def.to_def_id();
- let child_args = GenericArgs::identity_for_item(tcx, did);
- let args = tcx.mk_args_from_iter(parent_args.into_iter().chain(child_args.into_iter()));
- debug!(?args);
-
- let span = tcx.def_span(def);
- let uneval = UnevaluatedConst::new(did, args);
- debug!(?span, ?param_env);
-
- match tcx.const_eval_resolve(param_env, uneval, Some(span)) {
- Ok(val) => {
- debug!("evaluated const value");
- Self::Val(val, ty)
- }
- Err(_) => {
- debug!("error encountered during evaluation");
- // Error was handled in `const_eval_resolve`. Here we just create a
- // new unevaluated const and error hard later in codegen
- Self::Unevaluated(
- UnevaluatedConst {
- def: did,
- args: GenericArgs::identity_for_item(tcx, did),
- promoted: None,
- },
- ty,
- )
- }
- }
- }
-
pub fn from_ty_const(c: ty::Const<'tcx>, tcx: TyCtxt<'tcx>) -> Self {
match c.kind() {
ty::ConstKind::Value(valtree) => {
diff --git a/compiler/rustc_middle/src/ty/consts.rs b/compiler/rustc_middle/src/ty/consts.rs
index 0f5817c78e0a6..d0a1c94329221 100644
--- a/compiler/rustc_middle/src/ty/consts.rs
+++ b/compiler/rustc_middle/src/ty/consts.rs
@@ -216,6 +216,10 @@ impl<'tcx> Const<'tcx> {
}
}
+ // FIXME(const_generics): We currently have to special case parameters because `min_const_generics`
+ // does not provide the parents generics to anonymous constants. We still allow generic const
+ // parameters by themselves however, e.g. `N`. These constants would cause an ICE if we were to
+ // ever try to substitute the generic parameters in their bodies.
match expr.kind {
hir::ExprKind::Path(hir::QPath::Resolved(
_,
diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs
index 6541b4f6a3e0b..e01ee45180f54 100644
--- a/compiler/rustc_mir_build/src/thir/cx/expr.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs
@@ -642,15 +642,33 @@ impl<'tcx> Cx<'tcx> {
}
}
hir::InlineAsmOperand::Const { ref anon_const } => {
- let value =
- mir::Const::from_anon_const(tcx, anon_const.def_id, self.param_env);
+ let value = mir::Const::Unevaluated(
+ mir::UnevaluatedConst {
+ def: anon_const.def_id.to_def_id(),
+ args: GenericArgs::identity_for_item(
+ self.tcx,
+ anon_const.def_id,
+ ),
+ promoted: None,
+ },
+ tcx.type_of(anon_const.def_id).instantiate_identity(),
+ );
let span = tcx.def_span(anon_const.def_id);
InlineAsmOperand::Const { value, span }
}
hir::InlineAsmOperand::SymFn { ref anon_const } => {
- let value =
- mir::Const::from_anon_const(tcx, anon_const.def_id, self.param_env);
+ let value = mir::Const::Unevaluated(
+ mir::UnevaluatedConst {
+ def: anon_const.def_id.to_def_id(),
+ args: GenericArgs::identity_for_item(
+ self.tcx,
+ anon_const.def_id,
+ ),
+ promoted: None,
+ },
+ tcx.type_of(anon_const.def_id).instantiate_identity(),
+ );
let span = tcx.def_span(anon_const.def_id);
InlineAsmOperand::SymFn { value, span }
From 82f23d56b758d87e5eee642946ad8a422e6542ba Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Thu, 5 Oct 2023 09:43:55 +0000
Subject: [PATCH 2/3] make sure we still eagerly emit errors
---
compiler/rustc_mir_build/src/thir/cx/expr.rs | 6 ++++--
tests/ui/asm/const-error.rs | 15 +++++++++++++++
tests/ui/asm/const-error.stderr | 9 +++++++++
3 files changed, 28 insertions(+), 2 deletions(-)
create mode 100644 tests/ui/asm/const-error.rs
create mode 100644 tests/ui/asm/const-error.stderr
diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs
index e01ee45180f54..b07ffe7293bad 100644
--- a/compiler/rustc_mir_build/src/thir/cx/expr.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs
@@ -652,7 +652,8 @@ impl<'tcx> Cx<'tcx> {
promoted: None,
},
tcx.type_of(anon_const.def_id).instantiate_identity(),
- );
+ )
+ .normalize(tcx, self.param_env);
let span = tcx.def_span(anon_const.def_id);
InlineAsmOperand::Const { value, span }
@@ -668,7 +669,8 @@ impl<'tcx> Cx<'tcx> {
promoted: None,
},
tcx.type_of(anon_const.def_id).instantiate_identity(),
- );
+ )
+ .normalize(tcx, self.param_env);
let span = tcx.def_span(anon_const.def_id);
InlineAsmOperand::SymFn { value, span }
diff --git a/tests/ui/asm/const-error.rs b/tests/ui/asm/const-error.rs
new file mode 100644
index 0000000000000..4e14becf74bef
--- /dev/null
+++ b/tests/ui/asm/const-error.rs
@@ -0,0 +1,15 @@
+// only-x86_64
+// needs-asm-support
+
+#![feature(asm_const)]
+
+// Test to make sure that we emit const errors eagerly for inline asm
+
+use std::arch::asm;
+
+fn test<T>() {
+ unsafe { asm!("/* {} */", const 1 / 0); }
+ //~^ ERROR evaluation of
+}
+
+fn main() {}
diff --git a/tests/ui/asm/const-error.stderr b/tests/ui/asm/const-error.stderr
new file mode 100644
index 0000000000000..fe31183217726
--- /dev/null
+++ b/tests/ui/asm/const-error.stderr
@@ -0,0 +1,9 @@
+error[E0080]: evaluation of `test::<T>::{constant#0}` failed
+ --> $DIR/const-error.rs:11:37
+ |
+LL | unsafe { asm!("/* {} */", const 1 / 0); }
+ | ^^^^^ attempt to divide `1_i32` by zero
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0080`.
From 8bf9c18914b8c474f15da39fa6ce3e2522d5baa5 Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Fri, 17 Nov 2023 23:49:07 +0000
Subject: [PATCH 3/3] Review comment
---
compiler/rustc_middle/src/mir/consts.rs | 11 ++++++++
compiler/rustc_mir_build/src/thir/cx/expr.rs | 28 ++++++--------------
2 files changed, 19 insertions(+), 20 deletions(-)
diff --git a/compiler/rustc_middle/src/mir/consts.rs b/compiler/rustc_middle/src/mir/consts.rs
index fa7fa8e8c74d2..d38df1b720104 100644
--- a/compiler/rustc_middle/src/mir/consts.rs
+++ b/compiler/rustc_middle/src/mir/consts.rs
@@ -219,6 +219,17 @@ pub enum Const<'tcx> {
}
impl<'tcx> Const<'tcx> {
+ pub fn identity_unevaluated(tcx: TyCtxt<'tcx>, def_id: DefId) -> ty::EarlyBinder<Const<'tcx>> {
+ ty::EarlyBinder::bind(Const::Unevaluated(
+ UnevaluatedConst {
+ def: def_id,
+ args: ty::GenericArgs::identity_for_item(tcx, def_id),
+ promoted: None,
+ },
+ tcx.type_of(def_id).skip_binder(),
+ ))
+ }
+
#[inline(always)]
pub fn ty(&self) -> Ty<'tcx> {
match self {
diff --git a/compiler/rustc_mir_build/src/thir/cx/expr.rs b/compiler/rustc_mir_build/src/thir/cx/expr.rs
index b07ffe7293bad..d3af1b7745ec0 100644
--- a/compiler/rustc_mir_build/src/thir/cx/expr.rs
+++ b/compiler/rustc_mir_build/src/thir/cx/expr.rs
@@ -642,34 +642,22 @@ impl<'tcx> Cx<'tcx> {
}
}
hir::InlineAsmOperand::Const { ref anon_const } => {
- let value = mir::Const::Unevaluated(
- mir::UnevaluatedConst {
- def: anon_const.def_id.to_def_id(),
- args: GenericArgs::identity_for_item(
- self.tcx,
- anon_const.def_id,
- ),
- promoted: None,
- },
- tcx.type_of(anon_const.def_id).instantiate_identity(),
+ let value = mir::Const::identity_unevaluated(
+ tcx,
+ anon_const.def_id.to_def_id(),
)
+ .instantiate_identity()
.normalize(tcx, self.param_env);
let span = tcx.def_span(anon_const.def_id);
InlineAsmOperand::Const { value, span }
}
hir::InlineAsmOperand::SymFn { ref anon_const } => {
- let value = mir::Const::Unevaluated(
- mir::UnevaluatedConst {
- def: anon_const.def_id.to_def_id(),
- args: GenericArgs::identity_for_item(
- self.tcx,
- anon_const.def_id,
- ),
- promoted: None,
- },
- tcx.type_of(anon_const.def_id).instantiate_identity(),
+ let value = mir::Const::identity_unevaluated(
+ tcx,
+ anon_const.def_id.to_def_id(),
)
+ .instantiate_identity()
.normalize(tcx, self.param_env);
let span = tcx.def_span(anon_const.def_id);