Index: clang/include/clang/Analysis/Analyses/UnsafeBufferUsageGadgets.def
===================================================================
--- clang/include/clang/Analysis/Analyses/UnsafeBufferUsageGadgets.def
+++ clang/include/clang/Analysis/Analyses/UnsafeBufferUsageGadgets.def
@@ -21,6 +21,7 @@
 UNSAFE_GADGET(Increment)
 UNSAFE_GADGET(Decrement)
 UNSAFE_GADGET(ArraySubscript)
+UNSAFE_GADGET(UnsafeBufferUsageAttr)
 
 #undef SAFE_GADGET
 #undef UNSAFE_GADGET
Index: clang/include/clang/Basic/Attr.td
===================================================================
--- clang/include/clang/Basic/Attr.td
+++ clang/include/clang/Basic/Attr.td
@@ -3940,6 +3940,12 @@
   let Documentation = [ReleaseHandleDocs];
 }
 
+def UnsafeBufferUsage : InheritableAttr {
+  let Spellings = [Clang<"unsafe_buffer_usage">];
+  let Subjects = SubjectList<[Function]>;
+  let Documentation = [UnsafeBufferUsageDocs];
+}
+
 def DiagnoseAsBuiltin : InheritableAttr {
   let Spellings = [Clang<"diagnose_as_builtin">];
   let Args = [DeclArgument<Function, "Function">,
Index: clang/include/clang/Basic/AttrDocs.td
===================================================================
--- clang/include/clang/Basic/AttrDocs.td
+++ clang/include/clang/Basic/AttrDocs.td
@@ -6171,6 +6171,12 @@
   }];
 }
 
+def UnsafeBufferDocs : DocumentationCategory<"Unsafe Buffer Usage Attributes"> {
+  let Content = [{
+Unsafe Buffer usage attributes TODO: add documentation.
+  }];
+}
+
 def HandleDocs : DocumentationCategory<"Handle Attributes"> {
   let Content = [{
 Handles are a way to identify resources like files, sockets, and processes.
@@ -6236,6 +6242,21 @@
   }];
 }
 
+def UnsafeBufferUsageDocs : Documentation {
+  let Category = UnsafeBufferDocs;
+  let Content = [{
+If a function parameter is accessed in an unsafe manner,
+the corresponding function declaration is annotated with ``unsafe_buffer_usage``.
+
+.. code-block:: c++
+
+  [[clang::unsafe_buffer_usage]]
+  void foo(int* buf, int size) {
+      buf++;
+  }
+  }];
+}
+
 def DiagnoseAsBuiltinDocs : Documentation {
   let Category = DocCatFunction;
   let Content = [{
Index: clang/lib/Analysis/UnsafeBufferUsage.cpp
===================================================================
--- clang/lib/Analysis/UnsafeBufferUsage.cpp
+++ clang/lib/Analysis/UnsafeBufferUsage.cpp
@@ -330,6 +330,35 @@
     return {};
   }
 };
+
+/// A call of a function or method that performs unchecked buffer operations
+/// over one of its pointer parameters.
+class UnsafeBufferUsageAttrGadget : public UnsafeGadget {
+    const CallExpr *Op;
+
+public:
+    UnsafeBufferUsageAttrGadget(const MatchFinder::MatchResult &Result)
+      : UnsafeGadget(Kind::UnsafeBufferUsageAttr),
+        Op(Result.Nodes.getNodeAs<CallExpr>("call_expr")) {}
+
+  static bool classof(const Gadget *G) {
+    return G->getKind() == Kind::UnsafeBufferUsageAttr;
+  }
+
+  static Matcher matcher() {
+    return stmt(callExpr(callee(functionDecl(hasAttr(attr::UnsafeBufferUsage))))
+                          .bind("call_expr"));
+  }
+
+  const Stmt *getBaseStmt() const override { return Op; }
+
+  DeclUseList getClaimedVarUseSites() const override {
+    // FIXME: Not implemented yet. Returning {} is safe as it causes the gadget
+    // to block any attempts to fix variables that it could have otherwise
+    // claimed as known.
+    return {};
+  }
+};
 } // namespace
 
 namespace {
Index: clang/lib/Sema/SemaDeclAttr.cpp
===================================================================
--- clang/lib/Sema/SemaDeclAttr.cpp
+++ clang/lib/Sema/SemaDeclAttr.cpp
@@ -8335,6 +8335,15 @@
   D->addAttr(Attr::Create(S.Context, Argument, AL));
 }
 
+template<typename Attr>
+static void handleUnsafeBufferUsage(Sema &S, Decl *D, const ParsedAttr &AL) {
+//  StringRef Argument;
+//  if (!S.checkStringLiteralArgumentAttr(AL, 0, Argument))
+//    return;
+//  D->addAttr(Attr::Create(S.Context, Argument, AL));
+  D->addAttr(Attr::Create(S.Context, AL));
+}
+
 static void handleCFGuardAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
   // The guard attribute takes a single identifier argument.
 
@@ -9210,6 +9219,10 @@
   case ParsedAttr::AT_ReleaseHandle:
     handleHandleAttr<ReleaseHandleAttr>(S, D, AL);
     break;
+          
+  case ParsedAttr::AT_UnsafeBufferUsage:
+    handleUnsafeBufferUsage<UnsafeBufferUsageAttr>(S, D, AL);
+    break;
 
   case ParsedAttr::AT_UseHandle:
     handleHandleAttr<UseHandleAttr>(S, D, AL);
Index: clang/test/Misc/pragma-attribute-supported-attributes-list.test
===================================================================
--- clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -185,6 +185,7 @@
 // CHECK-NEXT: TestTypestate (SubjectMatchRule_function_is_member)
 // CHECK-NEXT: TrivialABI (SubjectMatchRule_record)
 // CHECK-NEXT: Uninitialized (SubjectMatchRule_variable_is_local)
+// CHECK-NEXT: UnsafeBufferUsage (SubjectMatchRule_function)
 // CHECK-NEXT: UseHandle (SubjectMatchRule_variable_is_parameter)
 // CHECK-NEXT: VecReturn (SubjectMatchRule_record)
 // CHECK-NEXT: VecTypeHint (SubjectMatchRule_function)
Index: clang/test/Sema/attr-unsafe_buffer_usage.cpp
===================================================================
--- /dev/null
+++ clang/test/Sema/attr-unsafe_buffer_usage.cpp
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1  -fsyntax-only -verify %s
+
+// Function annotations.
+[[clang::unsafe_buffer_usage]]
+void f(int *buf, int size);
+void g(int *buffer [[clang::unsafe_buffer_usage("buffer")]], int size); // expected-warning {{'unsafe_buffer_usage' attribute only applies to functions}}
Index: clang/test/SemaCXX/warn-unsafe-buffer-usage-function-attr.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/warn-unsafe-buffer-usage-function-attr.cpp
@@ -0,0 +1,31 @@
+// RUN: %clang_cc1 -std=c++20 -Wno-deprecated-declarations -Wunsafe-buffer-usage -verify %s
+
+[[clang::unsafe_buffer_usage]]
+void deprecatedFunction3();
+
+void deprecatedFunction4(int z);
+
+void someFunction();
+
+[[clang::unsafe_buffer_usage]]
+void overloading(int* x);
+
+void overloading(char c[]);
+
+void overloading(int* x, int size);
+
+[[clang::unsafe_buffer_usage]]
+void deprecatedFunction4(int z);
+
+void caller(int z, int* x, int size, char c[]) {
+    deprecatedFunction3(); // expected-warning{{unchecked operation on raw buffer in expression}}
+    deprecatedFunction4(z); // expected-warning{{unchecked operation on raw buffer in expression}}
+    someFunction();
+
+    overloading(x); // expected-warning{{unchecked operation on raw buffer in expression}}
+    overloading(x, size);
+    overloading(c);
+}
+
+[[clang::unsafe_buffer_usage]]
+void overloading(char c[]);