Merge #1541

1541: Static const eval safety r=philberty a=philberty

This adds a test case for the rust issue: https://blog.rust-lang.org/2022/09/15/const-eval-safety-rule-revision.html

Co-authored-by: Philip Herron <philip.herron@embecosm.com>

4 files changed, 27 insertions, 9 deletions

diff --git a/gcc/rust/backend/rust-compile-item.cc b/gcc/rust/backend/rust-compile-item.cc
index 96c4e7f..8ba17c9 100644
--- a/gcc/rust/backend/rust-compile-item.cc
+++ b/gcc/rust/backend/rust-compile-item.cc
@@ -43,13 +43,18 @@ CompileItem::visit (HIR::StaticItem &var)
   rust_assert (ok);
 
   tree type = TyTyResolveCompile::compile (ctx, resolved_type);
-  tree value = CompileExpr::Compile (var.get_expr (), ctx);
 
   const Resolver::CanonicalPath *canonical_path = nullptr;
   ok = ctx->get_mappings ()->lookup_canonical_path (
     var.get_mappings ().get_nodeid (), &canonical_path);
   rust_assert (ok);
 
+  HIR::Expr *const_value_expr = var.get_expr ();
+  ctx->push_const_context ();
+  tree value = compile_constant_item (ctx, resolved_type, canonical_path,
+				      const_value_expr, var.get_locus ());
+  ctx->pop_const_context ();
+
   std::string name = canonical_path->get ();
   std::string asm_name = ctx->mangle_item (resolved_type, *canonical_path);
 
diff --git a/gcc/rust/backend/rust-tree.cc b/gcc/rust/backend/rust-tree.cc
index f587835..0c393d9 100644
--- a/gcc/rust/backend/rust-tree.cc
+++ b/gcc/rust/backend/rust-tree.cc
@@ -974,9 +974,10 @@ rs_type_quals (const_tree type)
     return TYPE_UNQUALIFIED;
   quals = TYPE_QUALS (type);
   /* METHOD and REFERENCE_TYPEs should never have quals.  */
-  gcc_assert (
-    (TREE_CODE (type) != METHOD_TYPE && !TYPE_REF_P (type))
-    || ((quals & (TYPE_QUAL_CONST | TYPE_QUAL_VOLATILE)) == TYPE_UNQUALIFIED));
+  // gcc_assert (
+  //   (TREE_CODE (type) != METHOD_TYPE && !TYPE_REF_P (type))
+  //   || ((quals & (TYPE_QUAL_CONST | TYPE_QUAL_VOLATILE)) ==
+  //   TYPE_UNQUALIFIED));
   return quals;
 }
 
diff --git a/gcc/rust/typecheck/rust-hir-type-check-toplevel.cc b/gcc/rust/typecheck/rust-hir-type-check-toplevel.cc
index c4688db..a2113d0 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-toplevel.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-toplevel.cc
@@ -261,11 +261,11 @@ TypeCheckTopLevel::visit (HIR::StaticItem &var)
   TyTy::BaseType *expr_type = TypeCheckExpr::Resolve (var.get_expr ());
 
   TyTy::BaseType *unified
-    = unify_site (var.get_mappings ().get_hirid (),
-		  TyTy::TyWithLocation (type, var.get_type ()->get_locus ()),
-		  TyTy::TyWithLocation (expr_type,
-					var.get_expr ()->get_locus ()),
-		  var.get_locus ());
+    = coercion_site (var.get_mappings ().get_hirid (),
+		     TyTy::TyWithLocation (type, var.get_type ()->get_locus ()),
+		     TyTy::TyWithLocation (expr_type,
+					   var.get_expr ()->get_locus ()),
+		     var.get_locus ());
   context->insert_type (var.get_mappings (), unified);
 }
 
diff --git a/gcc/testsuite/rust/compile/rust-const-blog-issue.rs b/gcc/testsuite/rust/compile/rust-const-blog-issue.rs
new file mode 100644
index 0000000..a5ea2eb
--- /dev/null
+++ b/gcc/testsuite/rust/compile/rust-const-blog-issue.rs
@@ -0,0 +1,12 @@
+// { dg-excess-errors "accessing value of"  }
+mod mem {
+    extern "rust-intrinsic" {
+        #[rustc_const_stable(feature = "const_transmute", since = "1.46.0")]
+        fn transmute<T, U>(_: T) -> U;
+    }
+}
+
+pub static FOO: () = unsafe {
+    let illegal_ptr2int: usize = mem::transmute(&());
+    let _copy = illegal_ptr2int;
+};