[PATCH] D150036: [Clang] Correctly handle allocation in template arguments

Corentin Jabot via Phabricator via cfe-commits cfe-commits at lists.llvm.org
Mon May 8 07:28:30 PDT 2023


This revision was landed with ongoing or failed builds.
This revision was automatically updated to reflect the committed changes.
Closed by commit rG9857caf9d14f: [Clang] Correctly handle allocation in template arguments (authored by cor3ntin).

Changed prior to commit:
  https://reviews.llvm.org/D150036?vs=520356&id=520369#toc

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D150036/new/

https://reviews.llvm.org/D150036

Files:
  clang/docs/ReleaseNotes.rst
  clang/lib/AST/ExprConstant.cpp
  clang/test/SemaCXX/cxx2a-constexpr-dynalloc.cpp


Index: clang/test/SemaCXX/cxx2a-constexpr-dynalloc.cpp
===================================================================
--- clang/test/SemaCXX/cxx2a-constexpr-dynalloc.cpp
+++ clang/test/SemaCXX/cxx2a-constexpr-dynalloc.cpp
@@ -215,3 +215,27 @@
   }
   static_assert(h());
 }
+
+namespace GH62462 {
+
+class string {
+public:
+  char *mem;
+  constexpr string() {
+    this->mem = new char(1);
+  }
+  constexpr ~string() {
+    delete this->mem;
+  }
+  constexpr unsigned size() const { return 4; }
+};
+
+
+template <unsigned N>
+void test() {};
+
+void f() {
+    test<string().size()>();
+}
+
+}
Index: clang/lib/AST/ExprConstant.cpp
===================================================================
--- clang/lib/AST/ExprConstant.cpp
+++ clang/lib/AST/ExprConstant.cpp
@@ -15354,8 +15354,16 @@
   LValue LVal;
   LVal.set(Base);
 
-  if (!::EvaluateInPlace(Result.Val, Info, LVal, this) || Result.HasSideEffects)
-    return false;
+  {
+    // C++23 [intro.execution]/p5
+    // A full-expression is [...] a constant-expression
+    // So we need to make sure temporary objects are destroyed after having
+    // evaluating the expression (per C++23 [class.temporary]/p4).
+    FullExpressionRAII Scope(Info);
+    if (!::EvaluateInPlace(Result.Val, Info, LVal, this) ||
+        Result.HasSideEffects || !Scope.destroy())
+      return false;
+  }
 
   if (!Info.discardCleanups())
     llvm_unreachable("Unhandled cleanup; missing full expression marker?");
Index: clang/docs/ReleaseNotes.rst
===================================================================
--- clang/docs/ReleaseNotes.rst
+++ clang/docs/ReleaseNotes.rst
@@ -370,7 +370,7 @@
   (`#62192 <https://github.com/llvm/llvm-project/issues/62192>`_)
 - Fix crash when attempting to pass a non-pointer type as first argument of
   ``__builtin_assume_aligned``.
-  (`#62305 <https://github.com/llvm/llvm-project/issues/62305>`_) 
+  (`#62305 <https://github.com/llvm/llvm-project/issues/62305>`_)
 
 Bug Fixes to Compiler Builtins
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -416,6 +416,8 @@
   initialization.
   (`#61567 <https://github.com/llvm/llvm-project/issues/61567>`_)
 - Fix a crash when expanding a pack as the index of a subscript expression.
+- Fix handling of constexpr dynamic memory allocations in template
+  arguments. (`#62462 <https://github.com/llvm/llvm-project/issues/62462>`_)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^


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