diff --git a/gcc/libdiagnostics++.h b/gcc/libdiagnostics++.h
new file mode 100644
index 000000000000..14c84934a446
--- /dev/null
+++ b/gcc/libdiagnostics++.h
@@ -0,0 +1,595 @@
+/* A C++ wrapper API around libdiagnostics.h for emitting diagnostics.
+   Copyright (C) 2023-2024 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+
+GCC is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with GCC; see the file COPYING3.  If not see
+<http://www.gnu.org/licenses/>.  */
+
+#ifndef LIBDIAGNOSTICSPP_H
+#define LIBDIAGNOSTICSPP_H
+
+#include "libdiagnostics.h"
+
+namespace libdiagnostics {
+
+typedef diagnostic_line_num_t line_num_t;
+typedef diagnostic_column_num_t column_num_t;
+
+class file;
+class physical_location;
+class logical_location;
+class execution_path;
+class group;
+class manager;
+class diagnostic;
+
+/* Wrapper around a borrowed diagnostic_text_sink *.  */
+
+class text_sink
+{
+public:
+  text_sink (diagnostic_text_sink *inner)
+  : m_inner (inner)
+  {
+  }
+
+  void
+  set_source_printing_enabled (int value)
+  {
+    diagnostic_text_sink_set_source_printing_enabled (m_inner, value);
+  }
+
+  void
+  set_colorize (enum diagnostic_colorize colorize)
+  {
+    diagnostic_text_sink_set_colorize (m_inner, colorize);
+  }
+
+  void
+  set_labelled_source_colorization_enabled (int value)
+  {
+    diagnostic_text_sink_set_labelled_source_colorization_enabled (m_inner,
+								   value);
+  }
+
+  diagnostic_text_sink *m_inner;
+};
+
+/* Wrapper around a const diagnostic_file *.  */
+
+class file
+{
+public:
+  file () : m_inner (nullptr) {}
+  file (const diagnostic_file *file) : m_inner (file) {}
+  file (const file &other) : m_inner (other.m_inner) {}
+  file &operator= (const file &other) { m_inner = other.m_inner; return *this; }
+
+  const diagnostic_file * m_inner;
+};
+
+/* Wrapper around a const diagnostic_physical_location *.  */
+
+class physical_location
+{
+public:
+  physical_location () : m_inner (nullptr) {}
+
+  physical_location (const diagnostic_physical_location *location)
+  : m_inner (location)
+  {}
+
+  const diagnostic_physical_location *m_inner;
+};
+
+/* Wrapper around a const diagnostic_logical_location *.  */
+
+class logical_location
+{
+public:
+  logical_location () : m_inner (nullptr) {}
+
+  logical_location (const diagnostic_logical_location *logical_loc)
+  : m_inner (logical_loc)
+  {}
+
+  const diagnostic_logical_location *m_inner;
+};
+
+/* RAII class around a diagnostic_execution_path *.  */
+
+class execution_path
+{
+public:
+  execution_path () : m_inner (nullptr), m_owned (false) {}
+
+  execution_path (diagnostic_execution_path *path)
+  : m_inner (path), m_owned (true)
+  {}
+
+  execution_path (const diagnostic_execution_path *path)
+  : m_inner (const_cast<diagnostic_execution_path *> (path)),
+    m_owned (false)
+  {}
+
+  execution_path (const execution_path &other) = delete;
+  execution_path &operator= (const execution_path &other) = delete;
+
+  execution_path (execution_path &&other)
+  : m_inner (other.m_inner),
+    m_owned (other.m_owned)
+  {
+    other.m_inner = nullptr;
+    other.m_owned = false;
+  }
+
+  execution_path &operator= (execution_path &&other)
+  {
+    m_inner = other.m_inner;
+    m_owned = other.m_owned;
+    other.m_inner = nullptr;
+    other.m_owned = false;
+    return *this;
+  }
+
+  ~execution_path ()
+  {
+    if (m_owned)
+      diagnostic_execution_path_release (m_inner);
+  }
+
+  diagnostic_event_id
+  add_event (physical_location physical_loc,
+	     logical_location logical_loc,
+	     unsigned stack_depth,
+	     const char *fmt, ...)
+    LIBDIAGNOSTICS_PARAM_GCC_FORMAT_STRING (5, 6);
+
+  diagnostic_event_id
+  add_event_va (physical_location physical_loc,
+		logical_location logical_loc,
+		unsigned stack_depth,
+		const char *fmt,
+		va_list *args)
+    LIBDIAGNOSTICS_PARAM_GCC_FORMAT_STRING (5, 0);
+
+  diagnostic_execution_path *m_inner;
+  bool m_owned;
+};
+
+/* RAII class for starting/ending a group within a diagnostic_manager.  */
+
+class group
+{
+public:
+  group (manager &mgr);
+  ~group ();
+
+private:
+  manager &m_mgr;
+};
+
+/* Wrapper around a diagnostic *.  */
+
+class diagnostic
+{
+public:
+  diagnostic (::diagnostic *d) : m_inner (d) {}
+
+  void
+  set_cwe (unsigned cwe_id);
+
+  void
+  add_rule (const char *title, const char *url);
+
+  void
+  set_location (physical_location loc);
+
+  void
+  add_location_with_label (physical_location loc,
+			   const char *text);
+
+  void
+  set_logical_location (logical_location loc);
+
+  void
+  add_fix_it_hint_insert_before (physical_location loc,
+				 const char *addition);
+  void
+  add_fix_it_hint_insert_after (physical_location loc,
+				const char *addition);
+  void
+  add_fix_it_hint_replace (physical_location loc,
+			   const char *replacement);
+  void
+  add_fix_it_hint_delete (physical_location loc);
+
+  void
+  take_execution_path (execution_path path);
+
+  void
+  finish (const char *fmt, ...)
+    LIBDIAGNOSTICS_PARAM_MUST_BE_NON_NULL (2)
+    LIBDIAGNOSTICS_PARAM_GCC_FORMAT_STRING (2, 3);
+
+  void
+  finish_va (const char *fmt, va_list *args)
+    LIBDIAGNOSTICS_PARAM_MUST_BE_NON_NULL (2)
+    LIBDIAGNOSTICS_PARAM_GCC_FORMAT_STRING (2, 0);
+
+  ::diagnostic * const m_inner;
+};
+
+/* Wrapper around a diagnostic_manager *, possibly with ownership.  */
+
+class manager
+{
+public:
+  manager ()
+  : m_inner (diagnostic_manager_new ()),
+    m_owned (true)
+  {
+  }
+  manager (diagnostic_manager *inner, bool owned)
+  : m_inner (inner),
+    m_owned (owned)
+  {
+  }
+  ~manager ()
+  {
+    if (m_owned)
+      diagnostic_manager_release (m_inner);
+  }
+
+  manager (const manager &other) = delete;
+  manager (manager &&other)
+  : m_inner (other.m_inner),
+    m_owned (other.m_owned)
+  {
+    other.m_inner = nullptr;
+  }
+
+  void
+  set_tool_name (const char *value)
+  {
+    diagnostic_manager_set_tool_name (m_inner, value);
+  }
+
+  void
+  set_full_name (const char *value)
+  {
+    diagnostic_manager_set_full_name (m_inner, value);
+  }
+
+  void
+  set_version_string (const char *value)
+  {
+    diagnostic_manager_set_version_string (m_inner, value);
+  }
+
+  void
+  set_version_url (const char *value)
+  {
+    diagnostic_manager_set_version_url (m_inner, value);
+  }
+
+  text_sink
+  add_text_sink (FILE *dst_stream,
+		 enum diagnostic_colorize colorize)
+  {
+    return text_sink
+      (diagnostic_manager_add_text_sink (m_inner, dst_stream, colorize));
+  }
+
+  void
+  add_sarif_sink (FILE *dst_stream,
+		  file main_input_file,
+		  enum diagnostic_sarif_version version)
+  {
+    diagnostic_manager_add_sarif_sink (m_inner, dst_stream,
+				       main_input_file.m_inner,
+				       version);
+  }
+
+  void
+  write_patch (FILE *dst_stream)
+  {
+    diagnostic_manager_write_patch (m_inner, dst_stream);
+  }
+
+  /* Location management.  */
+
+  file
+  new_file (const char *name,
+	    const char *sarif_source_language)
+    LIBDIAGNOSTICS_PARAM_MUST_BE_NON_NULL (2)
+    LIBDIAGNOSTICS_PARAM_CAN_BE_NULL (3);
+
+  void
+  debug_dump (file f,
+	      FILE *out);
+
+  physical_location
+  new_location_from_file_and_line (file f, diagnostic_line_num_t line_num);
+
+  physical_location
+  new_location_from_file_line_column (file f,
+				      line_num_t line_num,
+				      column_num_t column_num);
+
+  physical_location
+  new_location_from_range (physical_location loc_caret,
+			   physical_location loc_start,
+			   physical_location loc_end);
+
+  void
+  debug_dump (physical_location loc,
+	      FILE *out);
+
+  logical_location
+  new_logical_location (enum diagnostic_logical_location_kind_t kind,
+			logical_location parent,
+			const char *short_name,
+			const char *fully_qualified_name,
+			const char *decorated_name);
+
+  void
+  debug_dump (logical_location loc,
+	      FILE *out);
+
+  execution_path
+  new_execution_path ();
+
+  diagnostic
+  begin_diagnostic (enum diagnostic_level level);
+
+
+  diagnostic_manager *m_inner;
+  bool m_owned;
+};
+
+// Implementation
+
+// class execution_path
+
+inline diagnostic_event_id
+execution_path::add_event (physical_location physical_loc,
+			   logical_location logical_loc,
+			   unsigned stack_depth,
+			   const char *fmt, ...)
+{
+  va_list args;
+  va_start (args, fmt);
+  diagnostic_event_id result = add_event_va (physical_loc,
+					     logical_loc,
+					     stack_depth,
+					     fmt, &args);
+  va_end (args);
+
+  return result;
+}
+
+inline diagnostic_event_id
+execution_path::add_event_va (physical_location physical_loc,
+			      logical_location logical_loc,
+			      unsigned stack_depth,
+			      const char *fmt,
+			      va_list *args)
+{
+  return diagnostic_execution_path_add_event_va (m_inner,
+						 physical_loc.m_inner,
+						 logical_loc.m_inner,
+						 stack_depth,
+						 fmt,
+						 args);
+}
+
+// class group
+
+inline
+group::group (manager &mgr)
+: m_mgr (mgr)
+{
+  diagnostic_manager_begin_group (m_mgr.m_inner);
+}
+
+inline
+group::~group ()
+{
+  diagnostic_manager_end_group (m_mgr.m_inner);
+}
+
+// class diagnostic
+
+inline void
+diagnostic::set_cwe (unsigned cwe_id)
+{
+  diagnostic_set_cwe (m_inner, cwe_id);
+}
+
+inline void
+diagnostic::add_rule (const char *title, const char *url)
+{
+  diagnostic_add_rule (m_inner, title, url);
+}
+
+inline void
+diagnostic::set_location (physical_location loc)
+{
+  diagnostic_set_location (m_inner, loc.m_inner);
+}
+
+inline void
+diagnostic::add_location_with_label (physical_location loc,
+				     const char *text)
+{
+  diagnostic_add_location_with_label (m_inner, loc.m_inner, text);
+}
+
+inline void
+diagnostic::set_logical_location (logical_location loc)
+{
+  diagnostic_set_logical_location (m_inner, loc.m_inner);
+}
+
+inline void
+diagnostic::add_fix_it_hint_insert_before (physical_location loc,
+					   const char *addition)
+{
+  diagnostic_add_fix_it_hint_insert_before (m_inner,
+					    loc.m_inner,
+					    addition);
+}
+
+inline void
+diagnostic::add_fix_it_hint_insert_after (physical_location loc,
+				const char *addition)
+{
+  diagnostic_add_fix_it_hint_insert_after (m_inner,
+					   loc.m_inner,
+					   addition);
+}
+
+inline void
+diagnostic::add_fix_it_hint_replace (physical_location loc,
+				     const char *replacement)
+{
+  diagnostic_add_fix_it_hint_replace (m_inner,
+				      loc.m_inner,
+				      replacement);
+}
+
+inline void
+diagnostic::add_fix_it_hint_delete (physical_location loc)
+{
+  diagnostic_add_fix_it_hint_delete (m_inner,
+				     loc.m_inner);
+}
+
+inline void
+diagnostic::take_execution_path (execution_path path)
+{
+  diagnostic_take_execution_path (m_inner,
+				  path.m_inner);
+  path.m_owned = false;
+}
+
+inline void
+diagnostic::finish (const char *fmt, ...)
+{
+  va_list ap;
+  va_start (ap, fmt);
+  diagnostic_finish_va (m_inner, fmt, &ap);
+  va_end (ap);
+}
+
+inline void
+diagnostic::finish_va (const char *fmt, va_list *args)
+{
+  diagnostic_finish_va (m_inner, fmt, args);
+}
+
+// class manager
+
+inline file
+manager::new_file (const char *name,
+		   const char *sarif_source_language)
+{
+  return file
+    (diagnostic_manager_new_file (m_inner, name, sarif_source_language));
+}
+
+inline physical_location
+manager::new_location_from_file_and_line (file f,
+					  diagnostic_line_num_t line_num)
+{
+  return physical_location
+    (diagnostic_manager_new_location_from_file_and_line (m_inner,
+							 f.m_inner,
+							 line_num));
+}
+
+inline physical_location
+manager::new_location_from_file_line_column (file f,
+					     line_num_t line_num,
+					     column_num_t column_num)
+{
+  return physical_location
+    (diagnostic_manager_new_location_from_file_line_column (m_inner,
+							    f.m_inner,
+							    line_num,
+							    column_num));
+}
+
+inline physical_location
+manager::new_location_from_range (physical_location loc_caret,
+				  physical_location loc_start,
+				  physical_location loc_end)
+{
+  return physical_location
+    (diagnostic_manager_new_location_from_range (m_inner,
+						 loc_caret.m_inner,
+						 loc_start.m_inner,
+						 loc_end.m_inner));
+}
+
+inline void
+manager::debug_dump (physical_location loc,
+		     FILE *out)
+{
+  diagnostic_manager_debug_dump_location (m_inner,
+					  loc.m_inner,
+					  out);
+}
+inline logical_location
+manager::new_logical_location (enum diagnostic_logical_location_kind_t kind,
+			       logical_location parent,
+			       const char *short_name,
+			       const char *fully_qualified_name,
+			       const char *decorated_name)
+{
+  return logical_location
+    (diagnostic_manager_new_logical_location (m_inner,
+					      kind,
+					      parent.m_inner,
+					      short_name,
+					      fully_qualified_name,
+					      decorated_name));
+}
+
+inline void
+manager::debug_dump (logical_location loc,
+		     FILE *out)
+{
+  diagnostic_manager_debug_dump_logical_location (m_inner,
+						  loc.m_inner,
+						  out);
+}
+
+inline execution_path
+manager::new_execution_path ()
+{
+  return execution_path (diagnostic_manager_new_execution_path (m_inner));
+}
+
+inline diagnostic
+manager::begin_diagnostic (enum diagnostic_level level)
+{
+  return diagnostic (diagnostic_begin (m_inner, level));
+}
+
+} // namespace libdiagnostics
+
+#endif // #ifndef LIBDIAGNOSTICSPP_H
