From 2228b3f08631b5e9b32e6b6c82e758fe4bcbbd60 Mon Sep 17 00:00:00 2001
From: Andreas Molzer <andreas.molzer@gmx.de>
Date: Sat, 17 Aug 2019 19:49:51 +0200
Subject: [PATCH] Derive HashStable for Allocation

Requires a manual implementation for Relocations since dereferencing to
SortedMap is not always implemented but that one is far more trivial.
Added fields could otherwise be silently forgotten since private fields
make destructing outside the module possible only with `..` pattern
which would then also be applicable to newly added public fields.
---
 src/librustc/ich/impls_ty.rs             | 26 ++++++++----------------
 src/librustc/mir/interpret/allocation.rs | 13 +++++++++++-
 2 files changed, 20 insertions(+), 19 deletions(-)

diff --git a/src/librustc/ich/impls_ty.rs b/src/librustc/ich/impls_ty.rs
index e33991bb1b6f..be7669fcad87 100644
--- a/src/librustc/ich/impls_ty.rs
+++ b/src/librustc/ich/impls_ty.rs
@@ -168,31 +168,21 @@ impl<'a> HashStable<StableHashingContext<'a>> for mir::interpret::AllocId {
     }
 }
 
-// Allocations treat their relocations specially
-impl<'a> HashStable<StableHashingContext<'a>> for mir::interpret::Allocation {
+// `Relocations` with default type parameters is a sorted map.
+impl<'a, Tag> HashStable<StableHashingContext<'a>>
+for mir::interpret::Relocations<Tag>
+where
+    Tag: HashStable<StableHashingContext<'a>>,
+{
     fn hash_stable<W: StableHasherResult>(
         &self,
         hcx: &mut StableHashingContext<'a>,
         hasher: &mut StableHasher<W>,
     ) {
-        let mir::interpret::Allocation {
-            relocations, align, mutability, size,
-            extra: _,
-            .. /* private bytes and undef_mask */
-        } = self;
-
-        let bytes = self.inspect_with_undef_and_ptr_outside_interpreter(0..self.len());
-        let undef_mask = self.undef_mask();
-
-        bytes.hash_stable(hcx, hasher);
-        relocations.len().hash_stable(hcx, hasher);
-        for reloc in relocations.iter() {
+        self.len().hash_stable(hcx, hasher);
+        for reloc in self.iter() {
             reloc.hash_stable(hcx, hasher);
         }
-        undef_mask.hash_stable(hcx, hasher);
-        size.hash_stable(hcx, hasher);
-        align.hash_stable(hcx, hasher);
-        mutability.hash_stable(hcx, hasher);
     }
 }
 
diff --git a/src/librustc/mir/interpret/allocation.rs b/src/librustc/mir/interpret/allocation.rs
index 61b237c0bb39..363fcaae5b26 100644
--- a/src/librustc/mir/interpret/allocation.rs
+++ b/src/librustc/mir/interpret/allocation.rs
@@ -13,7 +13,18 @@ use rustc_data_structures::sorted_map::SortedMap;
 use rustc_target::abi::HasDataLayout;
 use std::borrow::Cow;
 
-#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
+#[derive(
+    Clone,
+    Debug,
+    Eq,
+    PartialEq,
+    PartialOrd,
+    Ord,
+    Hash,
+    RustcEncodable,
+    RustcDecodable,
+    HashStable,
+)]
 pub struct Allocation<Tag=(),Extra=()> {
     /// The actual bytes of the allocation.
     /// Note that the bytes of a pointer represent the offset of the pointer.