Fix bug in 'value_of'.

Should work for getting the value of reflection of a local reference to an object having static storage duration.
bloomberg · Jun 24, 2024 · ebb430e · ebb430e
1 parent 5157802
commit ebb430e
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Showing 2 changed files with 19 additions and 3 deletions.
diff --git a/clang/lib/Sema/Metafunctions.cpp b/clang/lib/Sema/Metafunctions.cpp
@@ -1704,9 +1704,17 @@ bool value_of(APValue &Result, Sema &S, EvalFn Evaluator, QualType ResultTy,
       if (!VD->isUsableInConstantExpressions(S.Context))
         return true;
 
-      if (APValue *VarValue = VD->evaluateValue())
-        Value = *VarValue;
-      else
+      QualType QT = VD->getType();
+      if (auto *LVRT = dyn_cast<LValueReferenceType>(QT)) {
+        QT = LVRT->getPointeeType();
+      }
+
+      Expr *Synthesized = DeclRefExpr::Create(S.Context,
+                                              NestedNameSpecifierLoc(),
+                                              SourceLocation(), VD, false,
+                                              Range.getBegin(), QT,
+                                              VK_LValue, Decl, nullptr);
+      if (!Evaluator(Value, Synthesized, true))
         return true;
     } else if (isa<EnumConstantDecl>(Decl)) {
       Expr *Synthesized = DeclRefExpr::Create(S.Context,

diff --git a/libcxx/test/std/experimental/reflection/to-and-from-values.pass.cpp b/libcxx/test/std/experimental/reflection/to-and-from-values.pass.cpp
@@ -221,6 +221,14 @@ static_assert(type_of(value_of(^ref)) == ^int);
 constexpr std::pair<std::pair<int, bool>, int> p = {{1, true}, 2};
 static_assert(type_of(value_of(std::meta::reflect_object(p.first))) ==
               ^const std::pair<int, bool>);
+
+constexpr int g = 3;
+consteval std::meta::info fn() {
+    const int &r = g;
+    static_assert([:value_of(^r):] == 3);
+    return value_of(^r);
+}
+static_assert([:fn():] == 3);
 }  // namespace value_of_types
 
                              // ===================