diff --git a/gcc/libdiagnostics++.h b/gcc/libdiagnostics++.h
new file mode 100644
index 000000000000..8f412b07aa78
--- /dev/null
+++ b/gcc/libdiagnostics++.h
@@ -0,0 +1,378 @@
+/* A C++ wrapper API around libdiagnostics.h for emitting diagnostics.
+   Copyright (C) 2023 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 group;
+class manager;
+class diagnostic;
+
+/* Wrapper around a const diagnostic_file *.  */
+
+class file
+{
+public:
+  file (const diagnostic_file *file) : m_inner (file) {}
+
+  const diagnostic_file * const m_inner;
+};
+
+/* Wrapper around a const diagnostic_physical_location *.  */
+
+class physical_location
+{
+public:
+  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 * const m_inner;
+};
+
+/* 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
+  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
+  finish (const char *fmt, ...)
+    LIBDIAGNOSTICS_PARAM_MUST_BE_NON_NULL (2)
+    LIBDIAGNOSTICS_PARAM_GCC_FORMAT_STRING (2, 3);
+
+  ::diagnostic * const m_inner;
+};
+
+/* Wrapper around ownership of a diagnostic_manager *.  */
+
+class manager
+{
+public:
+  manager ()
+  : m_inner (diagnostic_manager_new ())
+  {
+  }
+  ~manager ()
+  {
+    diagnostic_manager_release (m_inner);
+  }
+
+  void
+  add_text_sink (FILE *dst_stream,
+		 enum diagnostic_colorize colorize)
+  {
+    diagnostic_manager_add_text_sink (m_inner, dst_stream, colorize);
+  }
+
+  void
+  add_sarif_sink (FILE *dst_stream,
+		  enum diagnostic_sarif_version version)
+  {
+    diagnostic_manager_add_sarif_sink (m_inner, dst_stream, 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);
+
+  diagnostic
+  begin_diagnostic (enum diagnostic_level level);
+
+
+  diagnostic_manager * const m_inner;
+};
+
+// Implementation
+
+// 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::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::finish (const char *fmt, ...)
+{
+  va_list ap;
+  va_start (ap, fmt);
+  diagnostic_finish_va (m_inner, fmt, &ap);
+  va_end (ap);
+}
+
+// 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 diagnostic
+manager::begin_diagnostic (enum diagnostic_level level)
+{
+  return diagnostic (diagnostic_begin (m_inner, level));
+}
+
+} // namespace libdiagnostics
+
+#endif // #ifndef LIBDIAGNOSTICSPP_H
diff --git a/gcc/testsuite/libdiagnostics.dg/libdiagnostics.exp b/gcc/testsuite/libdiagnostics.dg/libdiagnostics.exp
index bd50a5568a73..bcceb669d3ff 100644
--- a/gcc/testsuite/libdiagnostics.dg/libdiagnostics.exp
+++ b/gcc/testsuite/libdiagnostics.dg/libdiagnostics.exp
@@ -345,10 +345,10 @@ dg-init
 
 # Gather a list of all tests.
 
-# C tests within the testsuite: gcc/testsuite/libdiagnostics.dg/test-*.c
-set tests [find $srcdir/$subdir test-*.c]
-
-set tests [lsort $tests]
+# C and C++ tests within the testsuite: gcc/testsuite/libdiagnostics.dg/test-*.{c,c++}
+set c_tests [find $srcdir/$subdir test-*.c]
+set cxx_tests [find $srcdir/$subdir test-*.cc]
+set tests [concat $c_tests $cxx_tests]
 
 verbose "tests: $tests"
 
diff --git a/gcc/testsuite/libdiagnostics.dg/test-error-with-note.cc b/gcc/testsuite/libdiagnostics.dg/test-error-with-note.cc
new file mode 100644
index 000000000000..e20b9e04d6b1
--- /dev/null
+++ b/gcc/testsuite/libdiagnostics.dg/test-error-with-note.cc
@@ -0,0 +1,47 @@
+/* C++ example of emitting an error with an associated note.
+
+   Intended output is similar to:
+
+PATH/test-error-with-note.c:6: error: can't find 'foo'
+    6 | PRINT "hello world!";
+      |        ^~~~~~~~~~~~
+PATH/test-error-with-note.c:6: note: have you looked behind the couch?
+
+   along with the equivalent in SARIF.  */
+
+#include "libdiagnostics++.h"
+
+/*
+_________111111111122
+123456789012345678901
+PRINT "hello world!";
+*/
+const int line_num = __LINE__ - 2;
+
+int
+main ()
+{
+  libdiagnostics::manager mgr;
+
+  mgr.add_text_sink (stderr, DIAGNOSTIC_COLORIZE_IF_TTY);
+  mgr.add_sarif_sink (stderr, DIAGNOSTIC_SARIF_VERSION_2_1_0);
+
+  auto file = mgr.new_file (__FILE__, "c");
+  auto loc_start = mgr.new_location_from_file_line_column (file, line_num, 8);
+  auto loc_end = mgr.new_location_from_file_line_column (file, line_num, 19);
+  auto loc_range = mgr.new_location_from_range (loc_start,
+						loc_start,
+						loc_end);
+
+  libdiagnostics::group g (mgr);
+  
+  auto err (mgr.begin_diagnostic (DIAGNOSTIC_LEVEL_ERROR));
+  err.set_location (loc_range);
+  err.finish ("can't find %qs", "foo");
+
+  auto note = mgr.begin_diagnostic (DIAGNOSTIC_LEVEL_NOTE);
+  note.set_location (loc_range);
+  note.finish ("have you looked behind the couch?");
+
+  return 0;
+};
diff --git a/gcc/testsuite/libdiagnostics.dg/test-error.cc b/gcc/testsuite/libdiagnostics.dg/test-error.cc
new file mode 100644
index 000000000000..019307815bfb
--- /dev/null
+++ b/gcc/testsuite/libdiagnostics.dg/test-error.cc
@@ -0,0 +1,40 @@
+/* C++ example of emitting an error.
+
+   Intended output is similar to:
+
+PATH/test-error.cc:6: error: can't find 'foo'
+    6 | PRINT "hello world!";
+      |        ^~~~~~~~~~~~
+
+   along with the equivalent in SARIF.  */
+
+#include "libdiagnostics++.h"
+
+/*
+_________111111111122
+123456789012345678901
+PRINT "hello world!";
+*/
+const int line_num = __LINE__ - 2;
+
+int
+main ()
+{
+  libdiagnostics::manager mgr;
+
+  mgr.add_text_sink (stderr, DIAGNOSTIC_COLORIZE_IF_TTY);
+  mgr.add_sarif_sink (stderr, DIAGNOSTIC_SARIF_VERSION_2_1_0);
+
+  auto file = mgr.new_file (__FILE__, "c");
+  auto loc_start = mgr.new_location_from_file_line_column (file, line_num, 8);
+  auto loc_end = mgr.new_location_from_file_line_column (file, line_num, 19);
+  auto loc_range = mgr.new_location_from_range (loc_start,
+						loc_start,
+						loc_end);
+
+  libdiagnostics::diagnostic d (mgr.begin_diagnostic (DIAGNOSTIC_LEVEL_ERROR));
+  d.set_location (loc_range);
+  d.finish ("can't find %qs", "foo");
+
+  return 0;
+};
diff --git a/gcc/testsuite/libdiagnostics.dg/test-fix-it-hint.cc b/gcc/testsuite/libdiagnostics.dg/test-fix-it-hint.cc
new file mode 100644
index 000000000000..6af2641f2804
--- /dev/null
+++ b/gcc/testsuite/libdiagnostics.dg/test-fix-it-hint.cc
@@ -0,0 +1,44 @@
+/* C++ example of a fix-it hint, including patch generation.
+
+   Intended output is similar to:
+
+PATH/test-fix-it-hint.cc:19: error: unknown field 'colour'; did you mean 'color'
+   19 |   return p->colour;
+      |             ^~~~~~
+      |             color
+
+   along with the equivalent in SARIF, and a generated patch (on stderr) to
+   make the change.  */
+
+#include "libdiagnostics++.h"
+#include "test-helpers++.h"
+
+/*
+_________11111111112
+12345678901234567890
+  return p->colour;
+*/
+const int line_num = __LINE__ - 2;
+
+int
+main ()
+{
+  libdiagnostics::manager mgr;
+
+  mgr.add_text_sink (stderr, DIAGNOSTIC_COLORIZE_IF_TTY);
+  mgr.add_sarif_sink (stderr, DIAGNOSTIC_SARIF_VERSION_2_1_0);
+
+  auto file = mgr.new_file (__FILE__, "c");
+  auto loc_token = make_range (mgr, file, line_num, 13, 18);
+
+  auto d = mgr.begin_diagnostic (DIAGNOSTIC_LEVEL_ERROR);
+  d.set_location (loc_token);
+
+  d.add_fix_it_hint_replace (loc_token, "color");
+  
+  d.finish ("unknown field %qs; did you mean %qs", "colour", "color");
+
+  mgr.write_patch (stderr);
+
+  return 0;
+}
diff --git a/gcc/testsuite/libdiagnostics.dg/test-helpers++.h b/gcc/testsuite/libdiagnostics.dg/test-helpers++.h
new file mode 100644
index 000000000000..c8ff2def1ffa
--- /dev/null
+++ b/gcc/testsuite/libdiagnostics.dg/test-helpers++.h
@@ -0,0 +1,28 @@
+/* Common utility code shared between test cases.  */
+
+#ifndef TEST_HELPERSPP_H
+#define TEST_HELPERSPP_H
+
+namespace libdiagnostics {
+
+inline physical_location
+make_range (manager &mgr,
+	    file f,
+	    line_num_t line_num,
+	    column_num_t start_column,
+	    column_num_t end_column)
+{
+  auto loc_start = mgr.new_location_from_file_line_column (f,
+							   line_num,
+							   start_column);
+  auto loc_end = mgr.new_location_from_file_line_column (f,
+							 line_num,
+							 end_column);
+  return mgr.new_location_from_range (loc_start,
+				      loc_start,
+				      loc_end);
+}
+
+} // namespace libdiagnostics
+
+#endif /* #ifndef TEST_HELPERSPP_H */
diff --git a/gcc/testsuite/libdiagnostics.dg/test-labelled-ranges.cc b/gcc/testsuite/libdiagnostics.dg/test-labelled-ranges.cc
new file mode 100644
index 000000000000..35ccf74e1529
--- /dev/null
+++ b/gcc/testsuite/libdiagnostics.dg/test-labelled-ranges.cc
@@ -0,0 +1,43 @@
+/* C++ example of multiple locations, with labelling of ranges.
+
+   Intended output is similar to:
+
+PATH/test-labelled-ranges.cc:9: error: mismatching types: 'int' and 'const char *'
+   19 |   42 + "foo"
+      |   ~~ ^ ~~~~~
+      |   |    |
+      |   int  const char *
+
+   along with the equivalent in SARIF.  */
+
+#include "libdiagnostics++.h"
+#include "test-helpers++.h"
+
+/*
+_________11111111112
+12345678901234567890
+  42 + "foo"
+*/
+const int line_num = __LINE__ - 2;
+
+int
+main ()
+{
+  libdiagnostics::manager mgr;
+
+  mgr.add_text_sink (stderr, DIAGNOSTIC_COLORIZE_IF_TTY);
+  mgr.add_sarif_sink (stderr, DIAGNOSTIC_SARIF_VERSION_2_1_0);
+
+  libdiagnostics::file file = mgr.new_file (__FILE__, "c");
+  auto loc_operator = mgr.new_location_from_file_line_column (file, line_num, 6);
+
+  auto d (mgr.begin_diagnostic (DIAGNOSTIC_LEVEL_ERROR));
+  d.set_location (loc_operator);
+  d.add_location_with_label (make_range (mgr, file, line_num, 3, 4),
+			     "int");
+  d.add_location_with_label (make_range (mgr, file, line_num, 8, 12),
+			     "const char *");
+  d.finish ("mismatching types: %qs and %qs", "int", "const char *");
+  
+  return 0;
+}
