More workarounds for undefined behavior exposed when compiling in C++…

…14 with

-fsized-deallocation. Disable sized deallocation for all objects derived from
TrailingObjects, as we expect the storage allocated for these objects to be
larger than the size of their dynamic type.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259942 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Support/TrailingObjects.h

@@ -79,6 +79,11 @@ template <typename First> class AlignmentCalcHelper<First> {
 
 /// The base class for TrailingObjects* classes.
 class TrailingObjectsBase {
+public:
+  /// Disable sized deallocation for all objects with trailing object storage;
+  /// the inferred size will typically not be correct.
+  void operator delete(void *P) { return ::operator delete(P); }
+
 protected:
   /// OverloadToken's purpose is to allow specifying function overloads
   /// for different types, without actually taking the types as
@@ -290,7 +295,8 @@ class TrailingObjects : private trailing_objects_internal::TrailingObjectsImpl<
   }
 
 public:
-  // make this (privately inherited) class public.
+  // Make these (privately inherited) members public.
+  using ParentType::operator delete;
   using ParentType::OverloadToken;
 
   /// Returns a pointer to the trailing object array of the given type

lib/IR/AttributeImpl.h

@@ -171,6 +171,8 @@ class AttributeSetNode final
   void operator=(const AttributeSetNode &) = delete;
   AttributeSetNode(const AttributeSetNode &) = delete;
 public:
+  using TrailingObjects::operator delete;
+
   static AttributeSetNode *get(LLVMContext &C, ArrayRef<Attribute> Attrs);
 
   bool hasAttribute(Attribute::AttrKind Kind) const {
@@ -266,6 +268,8 @@ class AttributeSetImpl final
     }
   }
 
+  using TrailingObjects::operator delete;
+
   /// \brief Get the context that created this AttributeSetImpl.
   LLVMContext &getContext() { return Context; }
 

unittests/Support/TrailingObjectsTest.cpp

@@ -34,6 +34,7 @@ class Class1 final : protected TrailingObjects<Class1, short> {
     void *Mem = ::operator new(totalSizeToAlloc<short>(NumShorts));
     return new (Mem) Class1(ShortArray, NumShorts);
   }
+  using TrailingObjects::operator delete;
 
   short get(unsigned Num) const { return getTrailingObjects<short>()[Num]; }
 
@@ -78,6 +79,7 @@ class Class2 final : protected TrailingObjects<Class2, double, short> {
       *C->getTrailingObjects<double>() = D;
     return C;
   }
+  using TrailingObjects::operator delete;
 
   short getShort() const {
     if (!HasShort)