Rollup merge of #53850 - csmoe:const_to_alloc, r=RalfJung

Nuke the `const_to_allocation` query

Closes https://github.com/rust-lang/rust/issues/53847
r? @RalfJung
`./x.py check` works anyway, let's checkout tests from ci.

7 files changed, 15 insertions, 28 deletions

diff --git a/src/librustc/dep_graph/dep_node.rs b/src/librustc/dep_graph/dep_node.rs
index 90081d5b85e..dfe0a395ca1 100644
--- a/src/librustc/dep_graph/dep_node.rs
+++ b/src/librustc/dep_graph/dep_node.rs
@@ -75,7 +75,7 @@ use traits::query::{
     CanonicalPredicateGoal, CanonicalTypeOpProvePredicateGoal, CanonicalTypeOpNormalizeGoal,
 };
 use ty::{TyCtxt, FnSig, Instance, InstanceDef,
-         ParamEnv, ParamEnvAnd, Predicate, PolyFnSig, PolyTraitRef, Ty, self};
+         ParamEnv, ParamEnvAnd, Predicate, PolyFnSig, PolyTraitRef, Ty};
 use ty::subst::Substs;
 
 // erase!() just makes tokens go away. It's used to specify which macro argument
@@ -632,7 +632,6 @@ define_dep_nodes!( <'tcx>
     // queries). Making them anonymous avoids hashing the result, which
     // may save a bit of time.
     [anon] EraseRegionsTy { ty: Ty<'tcx> },
-    [anon] ConstToAllocation { val: &'tcx ty::Const<'tcx> },
 
     [input] Freevars(DefId),
     [input] MaybeUnusedTraitImport(DefId),
diff --git a/src/librustc/ty/query/config.rs b/src/librustc/ty/query/config.rs
index b5093d0a1fc..d32580181f8 100644
--- a/src/librustc/ty/query/config.rs
+++ b/src/librustc/ty/query/config.rs
@@ -198,12 +198,6 @@ impl<'tcx> QueryDescription<'tcx> for queries::super_predicates_of<'tcx> {
     }
 }
 
-impl<'tcx> QueryDescription<'tcx> for queries::const_to_allocation<'tcx> {
-    fn describe(_tcx: TyCtxt, val: &'tcx ty::Const<'tcx>) -> String {
-        format!("converting constant `{:?}` to an allocation", val)
-    }
-}
-
 impl<'tcx> QueryDescription<'tcx> for queries::erase_regions_ty<'tcx> {
     fn describe(_tcx: TyCtxt, ty: Ty<'tcx>) -> String {
         format!("erasing regions from `{:?}`", ty)
diff --git a/src/librustc/ty/query/mod.rs b/src/librustc/ty/query/mod.rs
index 6f61583e49b..88f599971c7 100644
--- a/src/librustc/ty/query/mod.rs
+++ b/src/librustc/ty/query/mod.rs
@@ -30,7 +30,7 @@ use middle::exported_symbols::{SymbolExportLevel, ExportedSymbol};
 use mir::interpret::ConstEvalResult;
 use mir::mono::{CodegenUnit, Stats};
 use mir;
-use mir::interpret::{GlobalId, Allocation};
+use mir::interpret::GlobalId;
 use session::{CompileResult, CrateDisambiguator};
 use session::config::OutputFilenames;
 use traits::{self, Vtable};
@@ -286,11 +286,6 @@ define_queries! { <'tcx>
         /// other items (such as enum variant explicit discriminants).
         [] fn const_eval: const_eval_dep_node(ty::ParamEnvAnd<'tcx, GlobalId<'tcx>>)
             -> ConstEvalResult<'tcx>,
-
-        /// Converts a constant value to a constant allocation
-        [] fn const_to_allocation: const_to_allocation(
-            &'tcx ty::Const<'tcx>
-        ) -> &'tcx Allocation,
     },
 
     TypeChecking {
@@ -706,12 +701,6 @@ fn erase_regions_ty<'tcx>(ty: Ty<'tcx>) -> DepConstructor<'tcx> {
     DepConstructor::EraseRegionsTy { ty }
 }
 
-fn const_to_allocation<'tcx>(
-    val: &'tcx ty::Const<'tcx>,
-) -> DepConstructor<'tcx> {
-    DepConstructor::ConstToAllocation { val }
-}
-
 fn type_param_predicates<'tcx>((item_id, param_id): (DefId, DefId)) -> DepConstructor<'tcx> {
     DepConstructor::TypeParamPredicates {
         item_id,
diff --git a/src/librustc/ty/query/plumbing.rs b/src/librustc/ty/query/plumbing.rs
index 0edb1aa79e7..215fba54499 100644
--- a/src/librustc/ty/query/plumbing.rs
+++ b/src/librustc/ty/query/plumbing.rs
@@ -1062,7 +1062,6 @@ pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>,
         DepKind::FulfillObligation |
         DepKind::VtableMethods |
         DepKind::EraseRegionsTy |
-        DepKind::ConstToAllocation |
         DepKind::NormalizeProjectionTy |
         DepKind::NormalizeTyAfterErasingRegions |
         DepKind::ImpliedOutlivesBounds |
diff --git a/src/librustc_mir/interpret/memory.rs b/src/librustc_mir/interpret/memory.rs
index 91fc6453446..59bebbb87a7 100644
--- a/src/librustc_mir/interpret/memory.rs
+++ b/src/librustc_mir/interpret/memory.rs
@@ -22,7 +22,7 @@ use std::ptr;
 
 use rustc::ty::{self, Instance, query::TyCtxtAt};
 use rustc::ty::layout::{self, Align, TargetDataLayout, Size, HasDataLayout};
-use rustc::mir::interpret::{Pointer, AllocId, Allocation, ScalarMaybeUndef, GlobalId,
+use rustc::mir::interpret::{Pointer, AllocId, Allocation, ConstValue, ScalarMaybeUndef, GlobalId,
                             EvalResult, Scalar, EvalErrorKind, AllocType, PointerArithmetic,
                             truncate};
 pub use rustc::mir::interpret::{write_target_uint, read_target_uint};
@@ -340,9 +340,12 @@ impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> Memory<'a, 'mir, 'tcx, M> {
             // no need to report anything, the const_eval call takes care of that for statics
             assert!(tcx.is_static(def_id).is_some());
             EvalErrorKind::ReferencedConstant(err).into()
-        }).map(|val| {
-            // FIXME We got our static (will be a ByRef), now we make a *copy*?!?
-            tcx.const_to_allocation(val)
+        }).map(|const_val| {
+            if let ConstValue::ByRef(_, allocation, _) = const_val.val {
+                allocation
+            } else {
+                bug!("Matching on non-ByRef static")
+            }
         })
     }
 
diff --git a/src/librustc_mir/lib.rs b/src/librustc_mir/lib.rs
index f91ff3642cd..d5148b09c4f 100644
--- a/src/librustc_mir/lib.rs
+++ b/src/librustc_mir/lib.rs
@@ -93,7 +93,6 @@ pub fn provide(providers: &mut Providers) {
     shim::provide(providers);
     transform::provide(providers);
     providers.const_eval = interpret::const_eval_provider;
-    providers.const_to_allocation = interpret::const_to_allocation_provider;
     providers.check_match = hair::pattern::check_match;
 }
 
diff --git a/src/librustc_typeck/check/mod.rs b/src/librustc_typeck/check/mod.rs
index bbb45c04e4e..7a13d8bdd4b 100644
--- a/src/librustc_typeck/check/mod.rs
+++ b/src/librustc_typeck/check/mod.rs
@@ -94,7 +94,7 @@ use rustc::infer::{self, InferCtxt, InferOk, RegionVariableOrigin};
 use rustc::infer::anon_types::AnonTypeDecl;
 use rustc::infer::type_variable::{TypeVariableOrigin};
 use rustc::middle::region;
-use rustc::mir::interpret::{GlobalId};
+use rustc::mir::interpret::{ConstValue, GlobalId};
 use rustc::ty::subst::{CanonicalSubsts, UnpackedKind, Subst, Substs};
 use rustc::traits::{self, ObligationCause, ObligationCauseCode, TraitEngine};
 use rustc::ty::{self, Ty, TyCtxt, GenericParamDefKind, Visibility, ToPredicate, RegionKind};
@@ -1375,7 +1375,11 @@ fn maybe_check_static_with_link_section(tcx: TyCtxt, id: DefId, span: Span) {
     };
     let param_env = ty::ParamEnv::reveal_all();
     if let Ok(static_) = tcx.const_eval(param_env.and(cid)) {
-        let alloc = tcx.const_to_allocation(static_);
+        let alloc = if let ConstValue::ByRef(_, allocation, _) = static_.val {
+            allocation
+        } else {
+            bug!("Matching on non-ByRef static")
+        };
         if alloc.relocations.len() != 0 {
             let msg = "statics with a custom `#[link_section]` must be a \
                        simple list of bytes on the wasm target with no \