[clang] [RFC] Initial implementation of P2719 (PR #113510)

[Oliver Hunt via cfe-commits]

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@@ -2527,6 +2527,32 @@ class FunctionDecl : public DeclaratorDecl,
   /// If this function is an allocation/deallocation function that takes
   /// the `std::nothrow_t` tag, return true through IsNothrow,
   bool isReplaceableGlobalAllocationFunction(
+      std::optional<unsigned> *AlignmentParam = nullptr,
+      bool *IsNothrow = nullptr) const {
+    if (isTypeAwareOperatorNewOrDelete())
+      return false;
+    return isUsableAsGlobalAllocationFunctionInConstantEvaluation(
+        AlignmentParam, IsNothrow);
+  }
+
+  /// Determines whether this function is one of the replaceable global
+  /// allocation functions described in isReplaceableGlobalAllocationFunction,
+  /// or is a function that may be treated as such during constant evaluation.
+  /// This adds support for potentially templated type aware global allocation
+  /// functions of the form:
+  ///    void *operator new(type-identity, std::size_t, std::align_val_t)
+  ///    void *operator new(type-identity, std::size_t, std::align_val_t, const std::nothrow_t &) noexcept;
+  ///    void *operator new[](type-identity, std::size_t, std::align_val_t)
+  ///    void *operator new[](type-identity, std::size_t, std::align_val_t, const std::nothrow_t &) noexcept;
+  ///    void operator delete(type-identity, void*, std::size_t, std::align_val_t) noexcept;
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ojhunt wrote:

clang-format wraps these as if they're comments which I've been unwrapping for now pending what the correct format should be.

https://github.com/llvm/llvm-project/pull/113510