[clang] ee5fc90 - [clang][bytecode] Check for invalid record decls when returning a pointer from an evaluation (#230907)

[via cfe-commits]

Author: Timm Baeder
Date: 2026-10-12T10:39:00+02:00
New Revision: ee5fc909fbb3dd4eb5145235abf6559b5424a3c8

URL: https://github.com/llvm/llvm-project/commit/ee5fc909fbb3dd4eb5145235abf6559b5424a3c8
DIFF: https://github.com/llvm/llvm-project/commit/ee5fc909fbb3dd4eb5145235abf6559b5424a3c8.diff

LOG: [clang][bytecode] Check for invalid record decls when returning a pointer from an evaluation (#230907)

We do allow creating such records for diagnostic purposes, but we
shouldn't allow returning them from an evaluation.

Added: 
    

Modified: 
    clang/lib/AST/ByteCode/EvaluationResult.cpp
    clang/test/AST/ByteCode/invalid.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/AST/ByteCode/EvaluationResult.cpp b/clang/lib/AST/ByteCode/EvaluationResult.cpp
index 30976fcf1d521..70f64568483fd 100644
--- a/clang/lib/AST/ByteCode/EvaluationResult.cpp
+++ b/clang/lib/AST/ByteCode/EvaluationResult.cpp
@@ -384,6 +384,11 @@ static bool lval(InterpState &S, const ASTContext &Ctx, const Pointer &Ptr,
   }
 
   if (const auto *VD = dyn_cast_if_present<VarDecl>(BaseVD)) {
+    // We might allow creating pointers into invalid records, but do not allow
+    // returning them from an evaluation.
+    if (const RecordDecl *TypeRD = VD->getType()->getAsRecordDecl();
+        TypeRD && TypeRD->isInvalidDecl())
+      return false;
     // Check if this is a thread-local variable.
     if (VD->getTLSKind()) {
       // FIXME: Diagnostic!

diff  --git a/clang/test/AST/ByteCode/invalid.cpp b/clang/test/AST/ByteCode/invalid.cpp
index cf859eb75dd90..a160c29169bc5 100644
--- a/clang/test/AST/ByteCode/invalid.cpp
+++ b/clang/test/AST/ByteCode/invalid.cpp
@@ -327,3 +327,14 @@ namespace StringLiteralDtor {
   static_assert(bar(), ""); // both-error {{not an integral constant expression}} \
                             // both-note {{in call to}}
 }
+
+namespace PointerIntoInvalidRecord {
+  template <auto V> auto foo = bar(V);
+  union U {
+    int baz;
+    union {
+      auto baz; // both-error {{'auto' not allowed in non-static union member}}
+    } internal;
+  } u;
+  template int *foo<&u.baz>; // both-error {{non-type template argument is not a constant expression}}
+}