[clang] [CIR] Add initial support for operator delete (PR #160574)

[Andy Kaylor via cfe-commits]

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@@ -332,6 +386,117 @@ static RValue emitNewDeleteCall(CIRGenFunction &cgf,
   return rv;
 }
 
+namespace {
+/// Calls the given 'operator delete' on a single object.
+struct CallObjectDelete final : EHScopeStack::Cleanup {
+  mlir::Value ptr;
+  const FunctionDecl *operatorDelete;
+  QualType elementType;
+
+  CallObjectDelete(mlir::Value ptr, const FunctionDecl *operatorDelete,
+                   QualType elementType)
+      : ptr(ptr), operatorDelete(operatorDelete), elementType(elementType) {}
+
+  void emit(CIRGenFunction &cgf) override {
+    cgf.emitDeleteCall(operatorDelete, ptr, elementType);
+  }
+
+  // This is a placeholder until EHCleanupScope is implemented.
+  size_t getSize() const override {
+    assert(!cir::MissingFeatures::ehCleanupScope());
+    return sizeof(CallObjectDelete);
+  }
+};
+} // namespace
+
+/// Emit the code for deleting a single object.
+static void emitObjectDelete(CIRGenFunction &cgf, const CXXDeleteExpr *de,
+                             Address ptr, QualType elementType) {
+  // C++11 [expr.delete]p3:
+  //   If the static type of the object to be deleted is different from its
+  //   dynamic type, the static type shall be a base class of the dynamic type
+  //   of the object to be deleted and the static type shall have a virtual
+  //   destructor or the behavior is undefined.
+  assert(!cir::MissingFeatures::emitTypeCheck());
+
+  const FunctionDecl *operatorDelete = de->getOperatorDelete();
+  assert(!operatorDelete->isDestroyingOperatorDelete());
+
+  // Find the destructor for the type, if applicable.  If the
+  // destructor is virtual, we'll just emit the vcall and return.
+  const CXXDestructorDecl *dtor = nullptr;
+  if (const auto *rd = elementType->getAsCXXRecordDecl()) {
+    if (rd->hasDefinition() && !rd->hasTrivialDestructor()) {
+      dtor = rd->getDestructor();
+
+      if (dtor->isVirtual()) {
+        cgf.cgm.errorNYI(de->getSourceRange(),
+                         "emitObjectDelete: virtual destructor");
+      }
+    }
+  }
+
+  // Make sure that we call delete even if the dtor throws.
+  // This doesn't have to a conditional cleanup because we're going
+  // to pop it off in a second.
+  cgf.ehStack.pushCleanup<CallObjectDelete>(
----------------
andykaylor wrote:

This will eventually ensure that the delete call happens even if an exception occurs, but even without exceptions, this is where the delete call is emitted.

https://github.com/llvm/llvm-project/pull/160574