[PATCH] D150435: [clang] Fix crash on attempt to initialize union with flexible array member

[Mariya Podchishchaeva via Phabricator via cfe-commits]

Fznamznon updated this revision to Diff 523723.
Fznamznon added a comment.

Move the test to a separate file, test C++ and MSVC compatibility mode


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D150435/new/

https://reviews.llvm.org/D150435

Files:
  clang/docs/ReleaseNotes.rst
  clang/lib/Sema/SemaInit.cpp
  clang/test/Sema/flexible-array-in-union.c


Index: clang/test/Sema/flexible-array-in-union.c
===================================================================
--- /dev/null
+++ clang/test/Sema/flexible-array-in-union.c
@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 %s -verify -fsyntax-only -DERROR
+// RUN: %clang_cc1 %s -verify -fsyntax-only -x c++
+// RUN: %clang_cc1 %s -verify -fsyntax-only -fms-compatibility
+// RUN: %clang_cc1 %s -verify -fsyntax-only -fms-compatibility -x c++
+
+// The test checks that an attempt to initialize union with flexible array
+// member with an initializer list doesn't crash clang.
+
+#ifdef ERROR
+// expected-error at +2 {{flexible array member 'x' in a union is not allowed}}
+#endif // ERROR
+union { char x[]; } r = {0};
+
+#ifndef ERROR
+// expected-no-diagnostics
+#endif // ERROR
+
Index: clang/lib/Sema/SemaInit.cpp
===================================================================
--- clang/lib/Sema/SemaInit.cpp
+++ clang/lib/Sema/SemaInit.cpp
@@ -811,7 +811,7 @@
       // order to leave them uninitialized, the ILE is expanded and the extra
       // fields are then filled with NoInitExpr.
       unsigned NumElems = numStructUnionElements(ILE->getType());
-      if (RDecl->hasFlexibleArrayMember())
+      if (!RDecl->isUnion() && RDecl->hasFlexibleArrayMember())
         ++NumElems;
       if (!VerifyOnly && ILE->getNumInits() < NumElems)
         ILE->resizeInits(SemaRef.Context, NumElems);
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -406,6 +406,8 @@
   when it had been instantiated from a partial template specialization with different
   template arguments on the containing class. This fixes:
   (`#60778 <https://github.com/llvm/llvm-project/issues/60778>`_).
+- Fix crash on attempt to initialize union with flexible array member.
+  (`#61746 <https://github.com/llvm/llvm-project/issues/61746>`_).
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


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