tools/gcc-plugins: frr-format

This provides the first reasonably-working version of the frr-format GCC
plugin.  I've only tested it with gcc 9.3.0.

Signed-off-by: David Lamparter <equinox@diac24.net>

14 files changed, 1776 insertions, 51 deletions

diff --git a/tools/gcc-plugins/.gitignore b/tools/gcc-plugins/.gitignore
new file mode 100644
index 000000000..dd8d0cb7e
--- /dev/null
+++ b/tools/gcc-plugins/.gitignore
@@ -0,0 +1,7 @@
+*.so
+*.o
+debian/.debhelper
+debian/files
+debian/*.substvars
+debian/gcc-9-frr-plugin
+!gcc-retain-typeinfo.patch
diff --git a/tools/gcc-plugins/COPYING.GPLv3 b/tools/gcc-plugins/COPYING.GPLv3
new file mode 100644
index 000000000..94a9ed024
--- /dev/null
+++ b/tools/gcc-plugins/COPYING.GPLv3
@@ -0,0 +1,674 @@
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+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program 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 of the License, or
+    (at your option) any later version.
+
+    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<http://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.
diff --git a/tools/gcc-plugins/Makefile b/tools/gcc-plugins/Makefile
new file mode 100644
index 000000000..d6edd745c
--- /dev/null
+++ b/tools/gcc-plugins/Makefile
@@ -0,0 +1,19 @@
+all: frr-format.so
+
+CXX=g++-9
+
+PLUGBASE=`$(CXX) -print-file-name=plugin`
+CPPFLAGS=-I$(PLUGBASE)/include -I$(PLUGBASE)/include/c-family
+
+frr-format.so: frr-format.o
+	$(CXX) -g -shared -o $@ $^
+
+frr-format.o: frr-format.c gcc-common.h
+	$(CXX) -g $(CPPFLAGS) -fPIC -Wall -Wextra -Wno-unused-parameter -c -o $@ $<
+
+install:
+	install -d $(DESTDIR)$(PLUGBASE)
+	install frr-format.so $(DESTDIR)$(PLUGBASE)
+
+clean:
+	rm -f frr-format.so frr-format.o
diff --git a/tools/gcc-plugins/README.md b/tools/gcc-plugins/README.md
new file mode 100644
index 000000000..94a9635e7
--- /dev/null
+++ b/tools/gcc-plugins/README.md
@@ -0,0 +1,99 @@
+frr-format GCC plugin
+=====================
+
+Context
+-------
+
+This plugin provides improved type checking for Linux kernel style printf
+extensions (i.e. `%pI4` printing `struct in_addr *` as `1.2.3.4`.)
+
+Other than additional warnings, (non-)usage of this plugin should not affect
+the build outcome.  It is perfectly fine to build FRR without this plugin.
+
+
+Binary Debian packages
+----------------------
+
+Can be found at [https://deb.nox.tf/devel/].
+
+
+GCC requirements
+----------------
+
+To use this plugin, you need a **patched 9.3.0** version of GCC using the
+[gcc-retain-typeinfo.patch] provided in this repo.  Without this patch, GCC
+strips type information too early during compilation, leaving to the plugin
+being unable to perform more meaningful type checks.  (Specifically, all
+`typedef` types will be "cooked down" to their final type.)
+
+(@eqvinox has discussed this one-line diff with some GCC people on their
+IRC channel around mid 2019, the consensus was that the line is an "early
+optimization" and removing it should not be harmful.  However, doing so is
+likely to break GCC's unit tests since warnings would print different types.)
+
+Other versions of gcc are not supported.  gcc 8 previously did work but isn't
+actively tested/maintained.  gcc 10 is not supported yet but may work.
+
+
+Usage
+-----
+
+First, all plugin-specific statements should be wrapped by an ifdef:
+
+```
+#ifdef _FRR_ATTRIBUTE_PRINTFRR
+...
+#endif
+```
+
+`_FRR_ATTRIBUTE_PRINTFRR` will be defined to the plugin's version (currently
+0x10000) whenever the plugin is loaded.
+
+Then, annotate extended printf functions with the `frr_format` attribute.
+This works exactly like the `format` attribute:
+
+```
+int printfn(const char *fmt, ...) __attribute__((frr_format("frr_printf", 1, 2)));
+```
+
+In the FRR codebase, use the `PRINTFRR` macro provided in
+[../../lib/compiler.h].
+
+Lastly, "declare" extensions with `#pragma FRR printfrr_ext`:
+```
+#ifdef _FRR_ATTRIBUTE_PRINTFRR
+#pragma FRR printfrr_ext "%pI4"  (struct in_addr *)
+#pragma FRR printfrr_ext "%pI4"  (in_addr_t *)
+#endif
+```
+
+Note that you can use multiple such lines if a particular extended printer
+works for more than one type (as seen above.)
+
+The pragma type "parameter" looks like a C cast but unfortunately due to GCC
+not exporting a good interface to proper type parsing, it is "ghetto parsed",
+with only `struct`, `union`, `enum` being properly supported.  `const` is
+ignored if it occurs as the first token.  (The plugin always accepts `const`
+parameters for printf since printf shouldn't change the passed data it's
+printing.)  The last token may be zero or more counts of `*`, note that
+qualifiers on the intermediate pointers (e.g. `const char * const *`) are not
+supported.
+
+
+TODOs and future direction
+--------------------------
+
+* support two-parameter extension printers that use the precision field
+  (e.g. `"%.*pI5" (int af, void *addr)` to print an IP address with the
+  address family in the "precision".
+
+* port to future GCC versions
+
+* get the one-liner patch upstreamed
+
+
+License
+-------
+
+This plugin is **derivative of GCC 9.x**.  It was created by copying off
+`c-format.c`.  It must therefore adhere to GCC's GPLv3+ license.
diff --git a/tools/gcc-plugins/debian/changelog b/tools/gcc-plugins/debian/changelog
new file mode 100644
index 000000000..62bbbcd46
--- /dev/null
+++ b/tools/gcc-plugins/debian/changelog
@@ -0,0 +1,5 @@
+gcc-frr-plugin (9.3.0d8+equi2) unstable; urgency=medium
+
+  * package created (+equi1 used during development, never released.)
+
+ -- David Lamparter <equinox-debian@diac24.net>  Sun, 29 Mar 2020 08:32:24 +0200
diff --git a/tools/gcc-plugins/debian/compat b/tools/gcc-plugins/debian/compat
new file mode 100644
index 000000000..48082f72f
--- /dev/null
+++ b/tools/gcc-plugins/debian/compat
@@ -0,0 +1 @@
+12
diff --git a/tools/gcc-plugins/debian/control b/tools/gcc-plugins/debian/control
new file mode 100644
index 000000000..6a9b886be
--- /dev/null
+++ b/tools/gcc-plugins/debian/control
@@ -0,0 +1,19 @@
+Source: gcc-frr-plugin
+Section: devel
+Priority: optional
+Maintainer: David Lamparter <equinox-debian@diac24.net>
+Build-Depends:
+ gcc-9-plugin-dev (=9.3.0-8+equi1),
+ debhelper (>= 12)
+Standards-Version: 4.4.1
+Homepage: https://www.frrouting.org/
+Vcs-Browser: https://github.com/FRRouting/frr/
+Vcs-Git: https://github.com/FRRouting/frr.git
+
+Package: gcc-9-frr-plugin
+Architecture: linux-any
+Depends:
+ gcc-9 (=9.3.0-8+equi1),
+ ${misc:Depends},
+ ${shlibs:Depends}
+Description: GCC plugin for FRRouting
diff --git a/tools/gcc-plugins/debian/copyright b/tools/gcc-plugins/debian/copyright
new file mode 100644
index 000000000..dcd9fa177
--- /dev/null
+++ b/tools/gcc-plugins/debian/copyright
@@ -0,0 +1,9 @@
+Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
+Upstream-Name: FRR
+Upstream-Contact: maintainers@frrouting.org, security@frrouting.org
+Source: https://www.frrouting.org/
+
+Files: *
+Copyright:
+  2019-2020 by David Lamparter
+  Code derived from GCC, please refer to gcc package copyright.
diff --git a/tools/gcc-plugins/debian/rules b/tools/gcc-plugins/debian/rules
new file mode 100755
index 000000000..f8f42ad33
--- /dev/null
+++ b/tools/gcc-plugins/debian/rules
@@ -0,0 +1,11 @@
+#!/usr/bin/make -f
+
+# standard Debian options & profiles
+
+export DEB_BUILD_MAINT_OPTIONS = hardening=+all
+
+%:
+	dh $@
+
+override_dh_auto_test:
+	true
diff --git a/tools/gcc-plugins/debian/source/format b/tools/gcc-plugins/debian/source/format
new file mode 100644
index 000000000..af745b310
--- /dev/null
+++ b/tools/gcc-plugins/debian/source/format
@@ -0,0 +1 @@
+3.0 (git)
diff --git a/tools/gcc-plugins/c-format.c b/tools/gcc-plugins/frr-format.c
index 572113d92..174f403d4 100644
--- a/tools/gcc-plugins/c-format.c
+++ b/tools/gcc-plugins/frr-format.c
@@ -1,5 +1,8 @@
 /* Check calls to formatted I/O functions (-Wformat).
-   Copyright (C) 1992-2018 Free Software Foundation, Inc.
+   Copyright (C) 1992-2019 Free Software Foundation, Inc.
+
+   Extended for FRR's printfrr() with Linux kernel style extensions
+   Copyright (C) 2019-2020  David Lamparter, for NetDEF, Inc.
 
 This file is part of GCC.
 
@@ -14,9 +17,11 @@ 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
+along with GCC; see the file COPYING.GPLv3.  If not see
 <http://www.gnu.org/licenses/>.  */
 
+#include "gcc-common.h"
+
 #include "config.h"
 #include "system.h"
 #include "coretypes.h"
@@ -25,10 +30,11 @@ along with GCC; see the file COPYING3.  If not see
 #include "c-common.h"
 #include "alloc-pool.h"
 #include "stringpool.h"
+#include "c-tree.h"
 #include "c-objc.h"
 #include "intl.h"
 #include "langhooks.h"
-#include "c-format.h"
+#include "frr-format.h"
 #include "diagnostic.h"
 #include "substring-locations.h"
 #include "selftest.h"
@@ -39,6 +45,12 @@ along with GCC; see the file COPYING3.  If not see
 #include "builtins.h"
 #include "attribs.h"
 #include "gcc-rich-location.h"
+#include "c-pretty-print.h"
+#include "c-pragma.h"
+
+extern struct cpp_reader *parse_in;
+
+#pragma GCC visibility push(hidden)
 
 /* Handle attributes associated with format checking.  */
 
@@ -55,6 +67,41 @@ struct function_format_info
   unsigned HOST_WIDE_INT first_arg_num;	/* number of first arg (zero for varargs) */
 };
 
+static GTY(()) tree local_uint64_t_node;
+static GTY(()) tree local_int64_t_node;
+
+static GTY(()) tree local_size_t_node;
+static GTY(()) tree local_ssize_t_node;
+static GTY(()) tree local_atomic_size_t_node;
+static GTY(()) tree local_atomic_ssize_t_node;
+static GTY(()) tree local_ptrdiff_t_node;
+
+static GTY(()) tree local_pid_t_node;
+static GTY(()) tree local_uid_t_node;
+static GTY(()) tree local_gid_t_node;
+static GTY(()) tree local_time_t_node;
+
+static GTY(()) tree local_socklen_t_node;
+static GTY(()) tree local_in_addr_t_node;
+
+static struct type_special {
+  tree *match;
+  tree *replace;
+  tree *cousin;
+} special_types[] = {
+  { &local_atomic_size_t_node,	&local_size_t_node,	&local_ssize_t_node, },
+  { &local_atomic_ssize_t_node,	&local_ssize_t_node,	&local_size_t_node, },
+  { &local_size_t_node,		NULL,			&local_ssize_t_node, },
+  { &local_ssize_t_node,	NULL,			&local_size_t_node, },
+  { &local_uint64_t_node,	NULL,			&local_int64_t_node, },
+  { &local_int64_t_node,	NULL,			&local_uint64_t_node, },
+  { &local_pid_t_node,		NULL,			&local_pid_t_node, },
+  { &local_uid_t_node,		NULL,			&local_uid_t_node, },
+  { &local_gid_t_node,		NULL,			&local_gid_t_node, },
+  { &local_time_t_node,		NULL,			&local_time_t_node, },
+  { NULL,			NULL,			NULL, }
+};
+
 static bool decode_format_attr (tree, function_format_info *, int);
 static int decode_format_type (const char *);
 
@@ -94,8 +141,9 @@ format_warning_at_char (location_t fmt_string_loc, tree format_string_cst,
   substring_loc fmt_loc (fmt_string_loc, string_type, char_idx, char_idx,
 			 char_idx);
 #if BUILDING_GCC_VERSION >= 9000
-  bool warned = format_warning_va (fmt_loc, NULL, UNKNOWN_LOCATION, NULL,
-				   NULL, opt, gmsgid, &ap);
+  format_string_diagnostic_t diag (fmt_loc, NULL, UNKNOWN_LOCATION, NULL,
+				   NULL);
+  bool warned = diag.emit_warning_va (opt, gmsgid, &ap);
 #else
   bool warned = format_warning_va (fmt_loc, UNKNOWN_LOCATION, NULL,
 				   opt, gmsgid, &ap);
@@ -129,7 +177,7 @@ valid_stringptr_type_p (tree strref)
 /* Handle a "format_arg" attribute; arguments as in
    struct attribute_spec.handler.  */
 tree
-handle_format_arg_attribute (tree *node, tree ARG_UNUSED (name),
+handle_frr_format_arg_attribute (tree *node, tree ARG_UNUSED (name),
 			     tree args, int flags, bool *no_add_attrs)
 {
   tree type = *node;
@@ -274,7 +322,7 @@ decode_format_attr (tree args, function_format_info *info, int validated_p)
   tree first_arg_num_expr
     = TREE_VALUE (TREE_CHAIN (TREE_CHAIN (args)));
 
-  if (TREE_CODE (format_type_id) != IDENTIFIER_NODE)
+  if (TREE_CODE (format_type_id) != STRING_CST)
     {
       gcc_assert (!validated_p);
       error ("unrecognized format specifier");
@@ -282,7 +330,7 @@ decode_format_attr (tree args, function_format_info *info, int validated_p)
     }
   else
     {
-      const char *p = IDENTIFIER_POINTER (format_type_id);
+      const char *p = TREE_STRING_POINTER (format_type_id);
 
       p = convert_format_name_to_system_name (p);
 
@@ -440,28 +488,36 @@ static const format_flag_pair printf_flag_pairs[] =
   { 0, 0, 0, 0 }
 };
 
+#define ETAB_SZ 128
+static kernel_ext_fmt ext_p[ETAB_SZ] = {
+  { NULL }
+};
+static kernel_ext_fmt ext_d[ETAB_SZ] = {
+  { NULL }
+};
 
 static const format_char_info print_char_table[] =
 {
   /* C89 conversion specifiers.  */
-  { "di",  0, STD_C89, { T89_I,   T99_SC,  T89_S,   T89_L,   T9L_LL,  TEX_LL,  T99_SST, T99_PD,  T99_IM,  BADLEN,  BADLEN,  BADLEN  }, "-wp0 +'I",  "i",  NULL },
-  { "oxX", 0, STD_C89, { T89_UI,  T99_UC,  T89_US,  T89_UL,  T9L_ULL, TEX_ULL, T99_ST,  T99_UPD, T99_UIM, BADLEN,  BADLEN,  BADLEN }, "-wp0#",     "i",  NULL },
-  { "u",   0, STD_C89, { T89_UI,  T99_UC,  T89_US,  T89_UL,  T9L_ULL, TEX_ULL, T99_ST,  T99_UPD, T99_UIM, BADLEN,  BADLEN,  BADLEN }, "-wp0'I",    "i",  NULL },
-  { "fgG", 0, STD_C89, { T89_D,   BADLEN,  BADLEN,  T99_D,   BADLEN,  T89_LD,  BADLEN,  BADLEN,  BADLEN,  TEX_D32, TEX_D64, TEX_D128 }, "-wp0 +#'I", "",   NULL },
-  { "eE",  0, STD_C89, { T89_D,   BADLEN,  BADLEN,  T99_D,   BADLEN,  T89_LD,  BADLEN,  BADLEN,  BADLEN,  TEX_D32, TEX_D64, TEX_D128 }, "-wp0 +#I",  "",   NULL },
-  { "c",   0, STD_C89, { T89_I,   BADLEN,  BADLEN,  T94_WI,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "-w",        "",   NULL },
-  { "s",   1, STD_C89, { T89_C,   BADLEN,  BADLEN,  T94_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "-wp",       "cR", NULL },
-  { "p",   1, STD_C89, { T89_V,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "-w",        "c",  NULL },
-  { "n",   1, STD_C89, { T89_I,   T99_SC,  T89_S,   T89_L,   T9L_LL,  BADLEN,  T99_SST, T99_PD,  T99_IM,  BADLEN,  BADLEN,  BADLEN }, "",          "W",  NULL },
+                      /* none,    hh,      h,       l,       ll,      L,       z,       t,       j,       H,       D,       DD     */
+  { "di",  0, STD_C89, { T89_I,   T99_SC,  T89_S,   T89_L,   T9L_LL,  TEX_S64, T99_SST, T99_PD,  T99_IM,  BADLEN,  BADLEN,  BADLEN },   "-wp0 +'I",  "i",  NULL, ext_d },
+  { "oxX", 0, STD_C89, { T89_UI,  T99_UC,  T89_US,  T89_UL,  T9L_ULL, TEX_U64, T99_ST,  T99_UPD, T99_UIM, BADLEN,  BADLEN,  BADLEN },   "-wp0#",     "i",  NULL, NULL },
+  { "u",   0, STD_C89, { T89_UI,  T99_UC,  T89_US,  T89_UL,  T9L_ULL, TEX_U64, T99_ST,  T99_UPD, T99_UIM, BADLEN,  BADLEN,  BADLEN },   "-wp0'I",    "i",  NULL, NULL },
+  { "fgG", 0, STD_C89, { T89_D,   BADLEN,  BADLEN,  T99_D,   BADLEN,  T89_LD,  BADLEN,  BADLEN,  BADLEN,  TEX_D32, TEX_D64, TEX_D128 }, "-wp0 +#'I", "",   NULL, NULL },
+  { "eE",  0, STD_C89, { T89_D,   BADLEN,  BADLEN,  T99_D,   BADLEN,  T89_LD,  BADLEN,  BADLEN,  BADLEN,  TEX_D32, TEX_D64, TEX_D128 }, "-wp0 +#I",  "",   NULL, NULL },
+  { "c",   0, STD_C89, { T89_I,   BADLEN,  BADLEN,  T94_WI,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN },   "-w",        "",   NULL, NULL },
+  { "s",   1, STD_C89, { T89_C,   BADLEN,  BADLEN,  T94_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN },   "-wp",       "cR", NULL, NULL },
+  { "p",   1, STD_C89, { T89_V,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN },   "-wp",       "c",  NULL, ext_p },
+  { "n",   1, STD_C89, { T89_I,   T99_SC,  T89_S,   T89_L,   T9L_LL,  BADLEN,  T99_SST, T99_PD,  T99_IM,  BADLEN,  BADLEN,  BADLEN },   "",          "W",  NULL, NULL },
   /* C99 conversion specifiers.  */
-  { "F",   0, STD_C99, { T99_D,   BADLEN,  BADLEN,  T99_D,   BADLEN,  T99_LD,  BADLEN,  BADLEN,  BADLEN,  TEX_D32, TEX_D64, TEX_D128 }, "-wp0 +#'I", "",   NULL },
-  { "aA",  0, STD_C99, { T99_D,   BADLEN,  BADLEN,  T99_D,   BADLEN,  T99_LD,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "-wp0 +#",   "",   NULL },
+  { "F",   0, STD_C99, { T99_D,   BADLEN,  BADLEN,  T99_D,   BADLEN,  T99_LD,  BADLEN,  BADLEN,  BADLEN,  TEX_D32, TEX_D64, TEX_D128 }, "-wp0 +#'I", "",   NULL, NULL },
+  { "aA",  0, STD_C99, { T99_D,   BADLEN,  BADLEN,  T99_D,   BADLEN,  T99_LD,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN },   "-wp0 +#",   "",   NULL, NULL },
   /* X/Open conversion specifiers.  */
-  { "C",   0, STD_EXT, { TEX_WI,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "-w",        "",   NULL },
-  { "S",   1, STD_EXT, { TEX_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "-wp",       "R",  NULL },
+  { "C",   0, STD_EXT, { TEX_WI,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN },   "-w",        "",   NULL, NULL },
+  { "S",   1, STD_EXT, { TEX_W,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN },   "-wp",       "R",  NULL, NULL },
   /* GNU conversion specifiers.  */
-  { "m",   0, STD_EXT, { T89_V,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN }, "-wp",       "",   NULL },
-  { NULL,  0, STD_C89, NOLENGTHS, NULL, NULL, NULL }
+  { "m",   0, STD_EXT, { T89_V,   BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN,  BADLEN },   "-wp",       "",   NULL, NULL },
+  { NULL,  0, STD_C89, NOLENGTHS, NULL, NULL, NULL, NULL }
 };
 
 /* This must be in the same order as enum format_type.  */
@@ -574,7 +630,18 @@ static void format_type_warning (const substring_loc &fmt_loc,
 				 tree,
 				 const format_kind_info *fki,
 				 int offset_to_type_start,
-				 char conversion_char);
+				 char conversion_char,
+				 const char *extra = NULL);
+
+static bool check_kef_type (const substring_loc &fmt_loc,
+		const struct kernel_ext_fmt *kef,
+		unsigned arg_num,
+		tree cur_param,
+		tree wanted_type,
+		const format_kind_info *fki,
+		int offset_to_type_start,
+		char conversion_char,
+		vec<location_t> *arglocs);
 
 /* Decode a format type from a string, returning the type, or
    format_type_error if not valid, in which case the caller should print an
@@ -1351,6 +1418,7 @@ class argument_parser
 
   bool
   check_argument_type (const format_char_info *fci,
+		       const struct kernel_ext_fmt *kef,
 		       const length_modifier &len_modifier,
 		       tree &wanted_type,
 		       const char *&wanted_type_name,
@@ -2158,6 +2226,7 @@ argument_parser::handle_conversions (const format_char_info *fci,
 bool
 argument_parser::
 check_argument_type (const format_char_info *fci,
+		     const struct kernel_ext_fmt *kef,
 		     const length_modifier &len_modifier,
 		     tree &wanted_type,
 		     const char *&wanted_type_name,
@@ -2278,6 +2347,41 @@ check_argument_type (const format_char_info *fci,
       check_format_types (fmt_loc, first_wanted_type, fki,
 			  offset_to_type_start,
 			  conversion_char, arglocs);
+
+      /* note printf extension type checks are *additional* - %p must always
+       * be pointer compatible, %d always int compatible.
+       */
+      if (!kef)
+	return true;
+
+      const struct kernel_ext_fmt *kef_now;
+      bool success;
+
+      for (kef_now = kef; kef_now->suffix && !strcmp (kef->suffix, kef_now->suffix); kef_now++)
+	{
+	  success = check_kef_type (fmt_loc, kef_now,
+	      first_wanted_type->arg_num,
+	      first_wanted_type->param,
+	      kef_now->type, fki, offset_to_type_start, conversion_char, arglocs);
+
+	  if (success)
+	    return true;
+	}
+
+      location_t param_loc;
+
+      if (EXPR_HAS_LOCATION (first_wanted_type->param))
+	param_loc = EXPR_LOCATION (first_wanted_type->param);
+      else if (arglocs)
+	{
+	  /* arg_num is 1-based.  */
+	  gcc_assert (first_wanted_type->arg_num > 0);
+	  param_loc = (*arglocs)[first_wanted_type->arg_num - 1];
+	}
+
+      format_type_warning (fmt_loc, param_loc, first_wanted_type,
+			   kef->type, TREE_TYPE (first_wanted_type->param),
+			   fki, offset_to_type_start, conversion_char);
     }
 
   return true;
@@ -2399,6 +2503,34 @@ check_format_info_main (format_check_results *res,
       if (!fci)
 	continue;
 
+      struct kernel_ext_fmt *etab = fci->kernel_ext;
+
+      if (etab && format_chars[0] >= 'A' && format_chars[0] <= 'Z')
+        {
+          struct kernel_ext_fmt *etab_end = etab + ETAB_SZ;
+
+          for (; etab < etab_end && etab->suffix; etab++)
+            {
+              if (!strncmp (etab->suffix, format_chars, strlen (etab->suffix)))
+                break;
+            }
+
+          if (!etab->suffix || etab == etab_end)
+            {
+	      format_warning_at_char (format_string_loc, format_string_cst,
+				      format_chars - orig_format_chars + 1,
+				      OPT_Wformat_,
+				      "unrecognized printf extension suffix");
+              etab = NULL;
+            }
+	  else
+	    {
+	      format_chars += strlen (etab->suffix);
+	    }
+        }
+      else
+	etab = NULL;
+
       flag_chars.validate (fki, fci, flag_specs, format_chars,
 			   format_string_cst,
 			   format_string_loc, orig_format_chars, format_char,
@@ -2487,7 +2619,7 @@ check_format_info_main (format_check_results *res,
       arg_parser.main_wanted_type.next = NULL;
 
       /* Finally. . .check type of argument against desired type!  */
-      if (!arg_parser.check_argument_type (fci, len_modifier,
+      if (!arg_parser.check_argument_type (fci, etab, len_modifier,
 					   wanted_type, wanted_type_name,
 					   suppressed,
 					   arg_num, params,
@@ -2569,6 +2701,43 @@ check_format_info_main (format_check_results *res,
                                ^ ^
                                | ` CONVERSION_CHAR: 'd'
                                type starts here.  */
+tree type_normalize (tree type, tree *cousin, tree target = NULL)
+{
+  while (1)
+    {
+      if (TREE_CODE (type) == FUNCTION_TYPE || TREE_CODE (type) == POINTER_TYPE)
+	return type;
+      if (target)
+	/* Strip off any "const" etc.  */
+        type = build_qualified_type (type, 0);
+      if (TREE_CODE (TYPE_NAME (type)) != TYPE_DECL)
+	return type;
+
+      if (target && (type == target || TYPE_NAME (type) == target))
+	return target;
+
+      struct type_special *t;
+      for (t = special_types; t->match; t++)
+        {
+	  if (!*t->match)
+	    continue;
+	  if (TYPE_NAME (type) != *t->match)
+	    continue;
+	  if (t->cousin && *t->cousin)
+	    *cousin = *t->cousin;
+	  if (t->replace)
+	    return *t->replace ? *t->replace : type;
+	  return type;
+        }
+
+      tree orig = DECL_ORIGINAL_TYPE (TYPE_NAME (type));
+      if (!orig)
+	return type;
+
+      type = orig;
+    }
+  return type;
+}
 
 static void
 check_format_types (const substring_loc &fmt_loc,
@@ -2581,6 +2750,7 @@ check_format_types (const substring_loc &fmt_loc,
     {
       tree cur_param;
       tree cur_type;
+      tree cur_type_cousin = NULL;
       tree orig_cur_type;
       tree wanted_type;
       int arg_num;
@@ -2597,7 +2767,17 @@ check_format_types (const substring_loc &fmt_loc,
       if (types->pointer_count == 0)
 	wanted_type = lang_hooks.types.type_promotes_to (wanted_type);
 
-      wanted_type = TYPE_MAIN_VARIANT (wanted_type);
+      switch (TREE_CODE (wanted_type))
+        {
+	  case IDENTIFIER_NODE:
+	    break;
+	  case TYPE_DECL:
+	    wanted_type = TYPE_MAIN_VARIANT (DECL_ORIGINAL_TYPE (wanted_type));
+	    break;
+	  default:
+	    wanted_type = TYPE_MAIN_VARIANT (wanted_type);
+	    break;
+        }
 
       cur_param = types->param;
       if (!cur_param)
@@ -2698,7 +2878,7 @@ check_format_types (const substring_loc &fmt_loc,
       if (i < types->pointer_count)
 	continue;
 
-      cur_type = TYPE_MAIN_VARIANT (cur_type);
+      cur_type = type_normalize (cur_type, &cur_type_cousin);
 
       /* Check whether the argument type is a character type.  This leniency
 	 only applies to certain formats, flagged with 'c'.  */
@@ -2707,9 +2887,58 @@ check_format_types (const substring_loc &fmt_loc,
 			  || cur_type == signed_char_type_node
 			  || cur_type == unsigned_char_type_node);
 
+      int compat = lang_hooks.types_compatible_p (wanted_type, cur_type);
       /* Check the type of the "real" argument, if there's a type we want.  */
-      if (lang_hooks.types_compatible_p (wanted_type, cur_type))
+      if ((TREE_CODE (wanted_type) != INTEGER_TYPE || types->pointer_count)
+	  && compat)
 	continue;
+      if (TREE_CODE (wanted_type) == INTEGER_TYPE && !types->pointer_count
+	  && compat)
+        {
+compat_inner:
+	  if (TREE_CODE (cur_param) == INTEGER_CST)
+	    continue;
+
+	  if (TREE_CODE (types->wanted_type) == TYPE_DECL
+	      && TREE_CODE (cur_type) == TYPE_DECL)
+	    {
+	      if (types->wanted_type == cur_type)
+		continue;
+	      format_type_warning (fmt_loc, param_loc, types,
+				   wanted_type, orig_cur_type, fki,
+				   offset_to_type_start, conversion_char,
+				   " (strict match required [A])");
+	      continue;
+	    }
+	  else if (TREE_CODE (types->wanted_type) == TYPE_DECL)
+	    {
+	      if (types->wanted_type == TYPE_NAME(cur_type))
+		continue;
+	      format_type_warning (fmt_loc, param_loc, types,
+				   wanted_type, orig_cur_type, fki,
+				   offset_to_type_start, conversion_char,
+				   " (strict match required [B])");
+	      continue;
+	    }
+	  else if (wanted_type == cur_type)
+	    continue;
+	  else if (cur_type_cousin)
+	    {
+	      format_type_warning (fmt_loc, param_loc, types,
+				   wanted_type, orig_cur_type, fki,
+				   offset_to_type_start, conversion_char,
+				   " (strict match required [C])");
+	    }
+
+	  /*
+	  format_type_warning (fmt_loc, param_loc, types,
+			       wanted_type, orig_cur_type, fki,
+			       offset_to_type_start, conversion_char,
+			       " (ultra-pedantic mode)");
+	  */
+	  continue;
+        }
+
       /* If we want 'void *', allow any pointer type.
 	 (Anything else would already have got a warning.)
 	 With -Wpedantic, only allow pointers to void and to character
@@ -2729,7 +2958,43 @@ check_format_types (const substring_loc &fmt_loc,
 	  && (TYPE_UNSIGNED (wanted_type)
 	      ? wanted_type == c_common_unsigned_type (cur_type)
 	      : wanted_type == c_common_signed_type (cur_type)))
-	continue;
+        {
+	  if (cur_type_cousin)
+	    {
+	      if (TREE_CODE (types->wanted_type) == TYPE_DECL
+		  && TREE_CODE (cur_type_cousin) == TYPE_DECL)
+		{
+		  if (types->wanted_type == cur_type_cousin)
+		    continue;
+		  format_type_warning (fmt_loc, param_loc, types,
+				       wanted_type, orig_cur_type, fki,
+				       offset_to_type_start, conversion_char,
+				       " (strict match required [X])");
+		  continue;
+		}
+	      else if (TREE_CODE (types->wanted_type) == TYPE_DECL)
+		{
+		  if (types->wanted_type == TYPE_NAME(cur_type_cousin))
+		    continue;
+		  format_type_warning (fmt_loc, param_loc, types,
+				       wanted_type, orig_cur_type, fki,
+				       offset_to_type_start, conversion_char,
+				       " (strict match required [Y])");
+		  continue;
+		}
+	      else if (wanted_type == cur_type_cousin)
+		continue;
+	      else
+	        {
+		  format_type_warning (fmt_loc, param_loc, types,
+				       wanted_type, orig_cur_type, fki,
+				       offset_to_type_start, conversion_char,
+				       " (strict match required [Z])");
+		}
+	    }
+
+	  goto compat_inner;
+	}
       /* Don't warn about differences merely in signedness if we know
 	 that the current type is integer-promoted and its original type
 	 was unsigned such as that it is in the range of WANTED_TYPE.  */
@@ -2764,6 +3029,101 @@ check_format_types (const substring_loc &fmt_loc,
     }
 }
 
+static bool
+check_kef_type (const substring_loc &fmt_loc,
+		const struct kernel_ext_fmt *kef,
+		unsigned arg_num,
+		tree cur_param,
+		tree wanted_type,
+		const format_kind_info *fki,
+		int offset_to_type_start,
+		char conversion_char,
+		vec<location_t> *arglocs)
+{
+  tree cur_type;
+  bool ok = true;
+  int i;
+
+  /* The following should not occur here.  */
+  gcc_assert (wanted_type);
+  gcc_assert (wanted_type != void_type_node || kef->ptrlevel);
+
+  if (TREE_CODE (wanted_type) == TYPE_DECL)
+    wanted_type = DECL_ORIGINAL_TYPE (wanted_type);
+
+  if (!cur_param)
+    return false;
+
+  cur_type = TREE_TYPE (cur_param);
+  if (cur_type == error_mark_node)
+    return false;
+
+  location_t param_loc = UNKNOWN_LOCATION;
+  if (EXPR_HAS_LOCATION (cur_param))
+    param_loc = EXPR_LOCATION (cur_param);
+  else if (arglocs)
+    {
+      /* arg_num is 1-based.  */
+      gcc_assert (arg_num > 0);
+      param_loc = (*arglocs)[arg_num - 1];
+    }
+  (void)param_loc;
+
+  STRIP_NOPS (cur_param);
+
+  /* Check the types of any additional pointer arguments
+     that precede the "real" argument.  */
+  for (i = 0; i < kef->ptrlevel; ++i)
+    {
+      if (TREE_CODE (cur_type) == POINTER_TYPE)
+	{
+	  cur_type = TREE_TYPE (cur_type);
+	  if (cur_type == error_mark_node)
+	    break;
+
+	  if (cur_param != 0 && TREE_CODE (cur_param) == ADDR_EXPR)
+	    cur_param = TREE_OPERAND (cur_param, 0);
+	  else
+	    cur_param = 0;
+
+	  /* If there are extra type qualifiers beyond the first
+	     indirection, then this makes the types technically
+	     incompatible.  */
+	  if (i > 0
+	      && pedantic
+	      && (TYPE_READONLY (cur_type)
+		  || TYPE_VOLATILE (cur_type)
+		  || TYPE_ATOMIC (cur_type)
+		  || TYPE_RESTRICT (cur_type)))
+	    warning (OPT_Wformat_, "extra type qualifiers in format "
+		     "argument (argument %d)",
+		     arg_num);
+
+	}
+      else
+	{
+	  ok = false;
+	  break;
+	}
+    }
+
+  if (i < kef->ptrlevel)
+    return ok;
+
+  int compat = lang_hooks.types_compatible_p (wanted_type, cur_type);
+
+  if (!compat)
+    return false;
+
+  tree cousin;
+  tree normal_type;
+
+  normal_type = type_normalize (cur_type, &cousin, wanted_type);
+
+  return normal_type == wanted_type;
+}
+
+
 /* Given type TYPE, attempt to dereference the type N times
    (e.g. from ("int ***", 2) to "int *")
 
@@ -3031,7 +3391,6 @@ get_corrected_substring (const substring_loc &fmt_loc,
   char_span line = location_get_source_line (start.file, start.line);
   if (!line)
     return NULL;
-#endif
 
   /* If we got this far, then we have the line containing the
      existing conversion specification.
@@ -3039,7 +3398,6 @@ get_corrected_substring (const substring_loc &fmt_loc,
      Generate a trimmed copy, containing the prefix part of the conversion
      specification, up to the (but not including) the length modifier.
      In the above example, this would be "%-+*.*".  */
-#if BUILDING_GCC_VERSION >= 9000
   int length_up_to_type = caret.column - start.column;
   char_span prefix_span = line.subspan (start.column - 1, length_up_to_type);
   char *prefix = prefix_span.xstrdup ();
@@ -3110,7 +3468,95 @@ class indirection_suffix
   int m_pointer_count;
 };
 
-#if BULDING_FOR_GCC >= 9000
+#if BUILDING_GCC_VERSION >= 9000
+/* not exported by GCC... need a local copy :( */
+class frr_range_label_for_type_mismatch : public range_label
+{
+ public:
+  frr_range_label_for_type_mismatch (tree labelled_type, tree other_type)
+  : m_labelled_type (labelled_type), m_other_type (other_type)
+  {
+  }
+
+  label_text get_text (unsigned range_idx) const OVERRIDE;
+
+ protected:
+  tree m_labelled_type;
+  tree m_other_type;
+};
+
+/* Print T to CPP.  */
+
+static void
+print_type (c_pretty_printer *cpp, tree t, bool *quoted)
+{
+  gcc_assert (TYPE_P (t));
+  struct obstack *ob = pp_buffer (cpp)->obstack;
+  char *p = (char *) obstack_base (ob);
+  /* Remember the end of the initial dump.  */
+  int len = obstack_object_size (ob);
+
+  tree name = TYPE_NAME (t);
+  if (name && TREE_CODE (name) == TYPE_DECL && DECL_NAME (name))
+    pp_identifier (cpp, lang_hooks.decl_printable_name (name, 2));
+  else
+    cpp->type_id (t);
+
+  /* If we're printing a type that involves typedefs, also print the
+     stripped version.  But sometimes the stripped version looks
+     exactly the same, so we don't want it after all.  To avoid
+     printing it in that case, we play ugly obstack games.  */
+  if (TYPE_CANONICAL (t) && t != TYPE_CANONICAL (t))
+    {
+      c_pretty_printer cpp2;
+      /* Print the stripped version into a temporary printer.  */
+      cpp2.type_id (TYPE_CANONICAL (t));
+      struct obstack *ob2 = cpp2.buffer->obstack;
+      /* Get the stripped version from the temporary printer.  */
+      const char *aka = (char *) obstack_base (ob2);
+      int aka_len = obstack_object_size (ob2);
+      int type1_len = obstack_object_size (ob) - len;
+
+      /* If they are identical, bail out.  */
+      if (aka_len == type1_len && memcmp (p + len, aka, aka_len) == 0)
+	return;
+
+      /* They're not, print the stripped version now.  */
+      if (*quoted)
+	pp_end_quote (cpp, pp_show_color (cpp));
+      pp_c_whitespace (cpp);
+      pp_left_brace (cpp);
+      pp_c_ws_string (cpp, _("aka"));
+      pp_c_whitespace (cpp);
+      if (*quoted)
+	pp_begin_quote (cpp, pp_show_color (cpp));
+      cpp->type_id (TYPE_CANONICAL (t));
+      if (*quoted)
+	pp_end_quote (cpp, pp_show_color (cpp));
+      pp_right_brace (cpp);
+      /* No further closing quotes are needed.  */
+      *quoted = false;
+    }
+}
+
+/* C-specific implementation of range_label::get_text () vfunc for
+   range_label_for_type_mismatch.  */
+
+label_text
+frr_range_label_for_type_mismatch::get_text (unsigned /*range_idx*/) const
+{
+  if (m_labelled_type == NULL_TREE)
+    return label_text (NULL, false);
+
+  c_pretty_printer cpp;
+  bool quoted = false;
+  print_type (&cpp, m_labelled_type, &quoted);
+  return label_text (xstrdup (pp_formatted_text (&cpp)), true);
+}
+
+#define range_label_for_type_mismatch frr_range_label_for_type_mismatch
+#endif
+
 /* Subclass of range_label for labelling the range in the format string
    with the type in question, adding trailing '*' for pointer_count.  */
 
@@ -3125,9 +3571,9 @@ class range_label_for_format_type_mismatch
   {
   }
 
-  label_text get_text () const FINAL OVERRIDE
+  label_text get_text (unsigned range_idx) const FINAL OVERRIDE
   {
-    label_text text = range_label_for_type_mismatch::get_text ();
+    label_text text = range_label_for_type_mismatch::get_text (range_idx);
     if (text.m_buffer == NULL)
       return text;
 
@@ -3143,7 +3589,6 @@ class range_label_for_format_type_mismatch
  private:
   int m_pointer_count;
 };
-#endif
 
 /* Give a warning about a format argument of different type from that expected.
    The range of the diagnostic is taken from WHOLE_FMT_LOC; the caret location
@@ -3184,7 +3629,8 @@ format_type_warning (const substring_loc &whole_fmt_loc,
 		     tree wanted_type, tree arg_type,
 		     const format_kind_info *fki,
 		     int offset_to_type_start,
-		     char conversion_char)
+		     char conversion_char,
+		     const char *extra)
 {
   enum format_specifier_kind kind = type->kind;
   const char *wanted_type_name = type->wanted_type_name;
@@ -3193,6 +3639,9 @@ format_type_warning (const substring_loc &whole_fmt_loc,
   int pointer_count = type->pointer_count;
   int arg_num = type->arg_num;
 
+  if (!extra)
+    extra = "";
+
   /* If ARG_TYPE is a typedef with a misleading name (for example,
      size_t but not the standard size_t expected by printf %zu), avoid
      printing the typedef name.  */
@@ -3215,21 +3664,31 @@ format_type_warning (const substring_loc &whole_fmt_loc,
   substring_loc fmt_loc (whole_fmt_loc);
   fmt_loc.set_caret_index (type->offset_loc - 1);
 
-#if BUILDING_FOR_GCC >= 9000
+#if BUILDING_GCC_VERSION >= 9000
   range_label_for_format_type_mismatch fmt_label (wanted_type, arg_type,
 						  pointer_count);
   range_label_for_type_mismatch param_label (arg_type, wanted_type);
+
+  /* Get a string for use as a replacement fix-it hint for the range in
+     fmt_loc, or NULL.  */
+  char *corrected_substring
+    = get_corrected_substring (fmt_loc, type, arg_type, fki,
+			       offset_to_type_start, conversion_char);
+  format_string_diagnostic_t diag (fmt_loc, &fmt_label, param_loc, &param_label,
+				   corrected_substring);
+# define format_warning_at_substring(a,b,c,d,e,...) \
+	diag.emit_warning(__VA_ARGS__)
 #else
 # define format_warning_at_substring(a,b,c,d,...) \
 	format_warning_at_substring(a,c,__VA_ARGS__)
-#endif
-
   /* Get a string for use as a replacement fix-it hint for the range in
      fmt_loc, or NULL.  */
   char *corrected_substring
     = get_corrected_substring (fmt_loc, type, arg_type, fki,
 			       offset_to_type_start, conversion_char);
 
+#endif
+
   if (wanted_type_name)
     {
       if (arg_type)
@@ -3237,19 +3696,19 @@ format_type_warning (const substring_loc &whole_fmt_loc,
 	  (fmt_loc, &fmt_label, param_loc, &param_label,
 	   corrected_substring, OPT_Wformat_,
 	   "%s %<%s%.*s%> expects argument of type %<%s%s%>, "
-	   "but argument %d has type %qT",
+	   "but argument %d has type %qT%s",
 	   gettext (kind_descriptions[kind]),
 	   (kind == CF_KIND_FORMAT ? "%" : ""),
 	   format_length, format_start,
-	   wanted_type_name, p, arg_num, arg_type);
+	   wanted_type_name, p, arg_num, arg_type, extra);
       else
 	format_warning_at_substring
 	  (fmt_loc, &fmt_label, param_loc, &param_label,
 	   corrected_substring, OPT_Wformat_,
-	   "%s %<%s%.*s%> expects a matching %<%s%s%> argument",
+	   "%s %<%s%.*s%> expects a matching %<%s%s%> argument%s",
 	   gettext (kind_descriptions[kind]),
 	   (kind == CF_KIND_FORMAT ? "%" : ""),
-	   format_length, format_start, wanted_type_name, p);
+	   format_length, format_start, wanted_type_name, p, extra);
     }
   else
     {
@@ -3258,25 +3717,26 @@ format_type_warning (const substring_loc &whole_fmt_loc,
 	  (fmt_loc, &fmt_label, param_loc, &param_label,
 	   corrected_substring, OPT_Wformat_,
 	   "%s %<%s%.*s%> expects argument of type %<%T%s%>, "
-	   "but argument %d has type %qT",
+	   "but argument %d has type %qT%s",
 	   gettext (kind_descriptions[kind]),
 	   (kind == CF_KIND_FORMAT ? "%" : ""),
 	   format_length, format_start,
-	   wanted_type, p, arg_num, arg_type);
+	   wanted_type, p, arg_num, arg_type, extra);
       else
 	format_warning_at_substring
 	  (fmt_loc, &fmt_label, param_loc, &param_label,
 	   corrected_substring, OPT_Wformat_,
-	   "%s %<%s%.*s%> expects a matching %<%T%s%> argument",
+	   "%s %<%s%.*s%> expects a matching %<%T%s%> argument%s",
 	   gettext (kind_descriptions[kind]),
 	   (kind == CF_KIND_FORMAT ? "%" : ""),
-	   format_length, format_start, wanted_type, p);
+	   format_length, format_start, wanted_type, p, extra);
     }
 
   free (corrected_substring);
 }
 
 
+#if 0
 /* Given a format_char_info array FCI, and a character C, this function
    returns the index into the conversion_specs where that specifier's
    data is located.  The character must exist.  */
@@ -3308,6 +3768,7 @@ find_length_info_modifier_index (const format_length_info *fli, int c)
   /* We shouldn't be looking for a non-existent modifier.  */
   gcc_unreachable ();
 }
+#endif
 
 #ifdef TARGET_FORMAT_TYPES
 extern const format_kind_info TARGET_FORMAT_TYPES[];
@@ -3378,7 +3839,7 @@ convert_format_name_to_system_name (const char *attr_name)
 /* Handle a "format" attribute; arguments as in
    struct attribute_spec.handler.  */
 tree
-handle_format_attribute (tree *node, tree ARG_UNUSED (name), tree args,
+handle_frr_format_attribute (tree *node, tree ARG_UNUSED (name), tree args,
 			 int flags, bool *no_add_attrs)
 {
   tree type = *node;
@@ -3611,3 +4072,386 @@ c_format_c_tests ()
 #endif /* CHECKING_P */
 
 // include "gt-c-family-c-format.h"
+
+static const struct attribute_spec frr_format_attribute_table[] =
+{
+  /* { name, min_len, max_len, decl_req, type_req, fn_type_req,
+       affects_type_identity, handler, exclude } */
+  { "frr_format",             3, 3, false, true,  true, false,
+			      handle_frr_format_attribute, NULL },
+  { "frr_format_arg",         1, 1, false, true,  true, false,
+			      handle_frr_format_arg_attribute, NULL },
+  { NULL,                     0, 0, false, false, false, false, NULL, NULL }
+};
+
+static void
+register_attributes (void *event_data, void *data)
+{
+  // warning (0, G_("Callback to register attributes"));
+  register_attribute (frr_format_attribute_table);
+}
+
+tree
+cb_walk_tree_fn (tree * tp, int * walk_subtrees, void * data ATTRIBUTE_UNUSED)
+{
+  if (TREE_CODE (*tp) != CALL_EXPR)
+    return NULL_TREE;
+
+  tree call_expr = *tp;
+
+  int nargs = call_expr_nargs(call_expr);
+  tree fn = CALL_EXPR_FN(call_expr);
+
+  if (!fn || TREE_CODE (fn) != ADDR_EXPR)
+    return NULL_TREE;
+
+  tree fndecl = TREE_OPERAND (fn, 0);
+  if (TREE_CODE (fndecl) != FUNCTION_DECL)
+    return NULL_TREE;
+
+#if 0
+  warning (0, G_("function call to %s, %d args"),
+           IDENTIFIER_POINTER (DECL_NAME (fndecl)),
+	   nargs);
+#endif
+
+  tree *fargs = (tree *) alloca (nargs * sizeof (tree));
+
+  for (int j = 0; j < nargs; j++)
+    {
+      tree arg = CALL_EXPR_ARG(call_expr, j);
+
+      /* For -Wformat undo the implicit passing by hidden reference
+	 done by convert_arg_to_ellipsis.  */
+      if (TREE_CODE (arg) == ADDR_EXPR
+	  && TREE_CODE (TREE_TYPE (arg)) == REFERENCE_TYPE)
+	fargs[j] = TREE_OPERAND (arg, 0);
+      else
+	fargs[j] = arg;
+    }
+
+  check_function_format (TYPE_ATTRIBUTES (TREE_TYPE (fndecl)), nargs, fargs, NULL);
+  return NULL_TREE;
+}
+
+static void
+setup_type (const char *name, tree *dst)
+{
+  tree tmp;
+
+  if (*dst && *dst != void_type_node)
+    return;
+
+  *dst = maybe_get_identifier (name);
+  if (!*dst)
+    return;
+
+  tmp = identifier_global_value (*dst);
+  if (tmp && TREE_CODE (tmp) != TYPE_DECL)
+    {
+      warning (0, "%<%s%> is not defined as a type", name);
+      *dst = NULL;
+      return;
+    }
+  if (tmp && TREE_CODE (tmp) == TYPE_DECL)
+    *dst = tmp;
+  else
+    *dst = NULL;
+}
+
+static void
+handle_finish_parse (void *event_data, void *data)
+{
+  tree fndecl = (tree) event_data;
+  gcc_assert (TREE_CODE (fndecl) == FUNCTION_DECL);
+
+  setup_type ("uint64_t", &local_uint64_t_node);
+  setup_type ("int64_t", &local_int64_t_node);
+
+  setup_type ("size_t", &local_size_t_node);
+  setup_type ("ssize_t", &local_ssize_t_node);
+  setup_type ("atomic_size_t", &local_atomic_size_t_node);
+  setup_type ("atomic_ssize_t", &local_atomic_ssize_t_node);
+  setup_type ("ptrdiff_t", &local_ptrdiff_t_node);
+
+  setup_type ("pid_t", &local_pid_t_node);
+  setup_type ("uid_t", &local_uid_t_node);
+  setup_type ("gid_t", &local_gid_t_node);
+  setup_type ("time_t", &local_time_t_node);
+
+  setup_type ("socklen_t", &local_socklen_t_node);
+  setup_type ("in_addr_t", &local_in_addr_t_node);
+
+  const format_char_info *fci;
+
+  for (fci = print_char_table; fci->format_chars; fci++)
+    {
+      if (!fci->kernel_ext)
+	continue;
+
+      struct kernel_ext_fmt *etab = fci->kernel_ext;
+      struct kernel_ext_fmt *etab_end = etab + ETAB_SZ;
+
+      for (; etab->suffix && etab < etab_end; etab++)
+        {
+	  tree identifier, node;
+
+          if (etab->type && etab->type != void_type_node)
+	    continue;
+
+	  identifier = maybe_get_identifier (etab->type_str);
+
+	  if (!identifier || identifier == error_mark_node)
+	    continue;
+
+	  if (etab->type_code)
+	    {
+	      node = identifier_global_tag (identifier);
+	      if (!node)
+	        continue;
+
+	      if (node->base.code != etab->type_code)
+	        {
+		  if (!etab->warned)
+		    {
+		      warning (0, "%qs tag category (struct/union/enum) mismatch", etab->type_str);
+		      etab->warned = true;
+		    }
+		  continue;
+	        }
+	    }
+	  else
+	    {
+	      node = identifier_global_value (identifier);
+	      if (!node)
+	        continue;
+
+	      if (TREE_CODE (node) != TYPE_DECL)
+		{
+		  if (!etab->warned)
+		    {
+		      warning (0, "%qs is defined as a non-type", etab->type_str);
+		      etab->warned = true;
+		    }
+		  continue;
+		}
+	      node = TREE_TYPE (node);
+	    }
+
+	  etab->type = node;
+        }
+    }
+
+  walk_tree (&DECL_SAVED_TREE (fndecl), cb_walk_tree_fn, NULL, NULL);
+}
+
+static void
+handle_pragma_printfrr_ext (cpp_reader *dummy)
+{
+  tree token = 0;
+  location_t loc;
+  enum cpp_ttype ttype;
+
+  ttype = pragma_lex (&token, &loc);
+  if (ttype != CPP_STRING)
+    {
+      error_at (loc, "%<#pragma FRR printfrr_ext%> requires string argument");
+      return;
+    }
+
+  const char *s = TREE_STRING_POINTER (token);
+
+  if (s[0] != '%')
+    {
+      error_at (loc, "%<#pragma FRR printfrr_ext%>: invalid format string, needs to start with '%%'");
+      return;
+    }
+
+  switch (s[1])
+    {
+      case 'p':
+      case 'd':
+      case 'i':
+        break;
+      default:
+        error_at (loc, "%<#pragma FRR printfrr_ext%>: invalid format string, needs to be %%p, %%d or %%i");
+        return;
+    }
+
+  const format_char_info *fci;
+
+  for (fci = print_char_table; fci->format_chars; fci++)
+    if (strchr (fci->format_chars, s[1]))
+      break;
+
+  gcc_assert (fci->format_chars);
+  gcc_assert (fci->kernel_ext);
+
+  struct kernel_ext_fmt *etab = fci->kernel_ext;
+  struct kernel_ext_fmt *etab_end = etab + ETAB_SZ;
+
+  switch (s[2])
+    {
+      case 'A' ... 'Z':
+        break;
+
+      default:
+        error_at (loc, "%<#pragma FRR printfrr_ext%>: invalid format string, suffix must start with an uppercase letter");
+        return;
+    }
+
+  /* -2 -- need to keep the sentinel at the end */
+  if (etab[ETAB_SZ - 2].suffix)
+    {
+      error_at (loc, "%<#pragma FRR printfrr_ext%>: out of space for format suffixes");
+      return;
+    }
+
+  for (; etab->suffix && etab < etab_end; etab++)
+    {
+      if (!strcmp(s + 2, etab->suffix))
+        {
+          memmove (etab + 1, etab, (etab_end - etab - 1) * sizeof (*etab));
+
+          if (0)
+            {
+              warning_at (loc, OPT_Wformat_,
+                          "%<#pragma FRR printfrr_ext%>: duplicate printf format suffix \"%s\"", s);
+              warning_at (etab->origin_loc, OPT_Wformat_,
+                          "%<#pragma FRR printfrr_ext%>: previous definition was here");
+              return;
+            }
+
+          break;
+        }
+
+      if (!strncmp(s + 2, etab->suffix, MIN(strlen(s + 2), strlen(etab->suffix))))
+        {
+          warning_at (loc, OPT_Wformat_,
+                      "%<#pragma FRR printfrr_ext%>: overlapping printf format suffix \"%s\"", s);
+          warning_at (etab->origin_loc, OPT_Wformat_,
+                      "%<#pragma FRR printfrr_ext%>: previous definition for \"%%%c%s\" was here", s[1], etab->suffix);
+          return;
+        }
+    }
+
+  gcc_assert (etab < etab_end);
+
+  memset (etab, 0, sizeof (*etab));
+  etab->suffix = xstrdup(s + 2);
+  etab->origin_loc = loc;
+  etab->type = void_type_node;
+
+  ttype = pragma_lex (&token, &loc);
+  if (ttype != CPP_OPEN_PAREN)
+    {
+      error_at (loc, "%<#pragma FRR printfrr_ext%> expected %<(%>");
+      goto out_drop;
+    }
+
+  ttype = pragma_lex (&token, &loc);
+
+  /* qualifiers */
+  if (ttype == CPP_NAME && !strcmp (IDENTIFIER_POINTER (token), "const"))
+    {
+      etab->t_const = true;
+      ttype = pragma_lex (&token, &loc);
+    }
+
+  /* tagged types */
+  if (ttype == CPP_NAME && !strcmp (IDENTIFIER_POINTER (token), "struct"))
+    {
+      etab->type_code = RECORD_TYPE;
+      ttype = pragma_lex (&token, &loc);
+    }
+  else if (ttype == CPP_NAME && !strcmp (IDENTIFIER_POINTER (token), "union"))
+    {
+      etab->type_code = UNION_TYPE;
+      ttype = pragma_lex (&token, &loc);
+    }
+  else if (ttype == CPP_NAME && !strcmp (IDENTIFIER_POINTER (token), "enum"))
+    {
+      etab->type_code = ENUMERAL_TYPE;
+      ttype = pragma_lex (&token, &loc);
+    }
+
+  /* type name */
+  if (ttype != CPP_NAME)
+    {
+      error_at (loc, "%<#pragma FRR printfrr_ext%>: expected typename identifier");
+      goto out_drop;
+    }
+
+  etab->type_str = xstrdup (IDENTIFIER_POINTER (token));
+
+  while ((ttype = pragma_lex (&token, &loc)) != CPP_CLOSE_PAREN)
+    {
+      switch (ttype) {
+      case CPP_NAME:
+        error_at (loc, "%<#pragma FRR printfrr_ext%>: unexpected identifier.  Note the only supported qualifier is \"const\".");
+        goto out_drop;
+
+      case CPP_MULT:
+        etab->ptrlevel++;
+        break;
+
+      case CPP_EOF:
+        error_at (loc, "%<#pragma FRR printfrr_ext%>: premature end of line, missing %<)%>");
+        goto out_drop;
+
+      default:
+        error_at (loc, "%<#pragma FRR printfrr_ext%>: unsupported token");
+        goto out_drop;
+      }
+    }
+
+  ttype = pragma_lex (&token, &loc);
+  if (ttype != CPP_EOF)
+    warning_at (loc, OPT_Wformat_,
+                "%<#pragma FRR printfrr_ext%>: garbage at end of line");
+
+  return;
+
+out_drop:
+  memset (etab, 0, sizeof (*etab));
+}
+
+static void
+register_pragma_printfrr_ext (void *event_data, void *data)
+{
+  c_register_pragma_with_expansion ("FRR", "printfrr_ext", handle_pragma_printfrr_ext);
+}
+
+static void
+define_vars (void *gcc_data, void *user_data)
+{
+  cpp_define (parse_in, "_FRR_ATTRIBUTE_PRINTFRR=0x10000");
+}
+
+#ifndef __visible
+#define __visible __attribute__((visibility("default")))
+#endif
+
+__visible int plugin_is_GPL_compatible;
+
+__visible int
+plugin_init (struct plugin_name_args *plugin_info,
+             struct plugin_gcc_version *version)
+{
+  const char *plugin_name = plugin_info->base_name;
+
+  if (!plugin_default_version_check(version, &gcc_version))
+    {
+      error(G_("incompatible gcc/plugin versions"));
+      return 1;
+    }
+
+  memset (ext_p, 0, sizeof (ext_p));
+  memset (ext_d, 0, sizeof (ext_d));
+
+  register_callback (plugin_name, PLUGIN_FINISH_PARSE_FUNCTION, handle_finish_parse, NULL);
+  register_callback (plugin_name, PLUGIN_ATTRIBUTES, register_attributes, NULL);
+  register_callback (plugin_name, PLUGIN_START_UNIT, define_vars, NULL);
+  register_callback (plugin_name, PLUGIN_PRAGMAS, register_pragma_printfrr_ext, NULL);
+  return 0;
+}
diff --git a/tools/gcc-plugins/c-format.h b/tools/gcc-plugins/frr-format.h
index d984d10e2..87d2049ed 100644
--- a/tools/gcc-plugins/c-format.h
+++ b/tools/gcc-plugins/frr-format.h
@@ -105,6 +105,23 @@ struct format_length_info
 };
 
 
+struct kernel_ext_fmt
+{
+	const char *suffix;
+
+	/* RECORD_TYPE, UNION_TYPE, ENUMERAL_TYPE, or NULL for typedef */
+	tree_code type_code;
+	int ptrlevel;
+	bool t_const;
+	bool warned;
+
+	const char *type_str;
+	GTY(()) tree type;
+
+	location_t origin_loc;
+};
+
+
 /* Structure describing the combination of a conversion specifier
    (or a set of specifiers which act identically) and a length modifier.  */
 struct format_type_detail
@@ -167,6 +184,8 @@ struct format_char_info
      arguments, only POINTER_COUNT, TYPES, and the "c", "R", and "W" flags
      in FLAGS2 are used.  */
   const struct format_char_info *chain;
+
+  struct kernel_ext_fmt *kernel_ext;
 };
 
 
@@ -271,6 +290,10 @@ struct format_kind_info
 #define T_LL	&long_long_integer_type_node
 #define T9L_LL	{ STD_C9L, NULL, T_LL }
 #define TEX_LL	{ STD_EXT, NULL, T_LL }
+#define T_U64	&local_uint64_t_node
+#define TEX_U64	{ STD_EXT, "uint64_t", T_U64 }
+#define T_S64	&local_int64_t_node
+#define TEX_S64	{ STD_EXT, "int64_t", T_S64 }
 #define T_S	&short_integer_type_node
 #define T89_S	{ STD_C89, NULL, T_S }
 #define T_UI	&unsigned_type_node
@@ -307,10 +330,10 @@ struct format_kind_info
 #define T_WI	&wint_type_node
 #define T94_WI	{ STD_C94, "wint_t", T_WI }
 #define TEX_WI	{ STD_EXT, "wint_t", T_WI }
-#define T_ST    &size_type_node
+#define T_ST    &local_size_t_node
 #define T99_ST	{ STD_C99, "size_t", T_ST }
-#define T_SST   &signed_size_type_node
-#define T99_SST	{ STD_C99, "signed size_t", T_SST }
+#define T_SST   &local_ssize_t_node
+#define T99_SST	{ STD_C99, "ssize_t", T_SST }
 #define T_PD    &ptrdiff_type_node
 #define T99_PD	{ STD_C99, "ptrdiff_t", T_PD }
 #define T_UPD   &unsigned_ptrdiff_type_node
diff --git a/tools/gcc-plugins/gcc-common.h b/tools/gcc-plugins/gcc-common.h
index e28e1a174..6b6c17231 100644
--- a/tools/gcc-plugins/gcc-common.h
+++ b/tools/gcc-plugins/gcc-common.h
@@ -165,8 +165,10 @@ void dump_gimple_stmt(pretty_printer *, gimple, int, int);
 #define TYPE_NAME_POINTER(node) IDENTIFIER_POINTER(TYPE_NAME(node))
 #define TYPE_NAME_LENGTH(node) IDENTIFIER_LENGTH(TYPE_NAME(node))
 
+#if BUILDING_GCC_VERSION < 9000
 /* should come from c-tree.h if only it were installed for gcc 4.5... */
 #define C_TYPE_FIELDS_READONLY(TYPE) TREE_LANG_FLAG_1(TYPE)
+#endif
 
 static inline tree build_const_char_string(int len, const char *str)
 {
diff --git a/tools/gcc-plugins/gcc-retain-typeinfo.patch b/tools/gcc-plugins/gcc-retain-typeinfo.patch
new file mode 100644
index 000000000..ec51f0be6
--- /dev/null
+++ b/tools/gcc-plugins/gcc-retain-typeinfo.patch
@@ -0,0 +1,11 @@
+--- a/src/gcc/c/c-typeck.c
++++ b/src/gcc/c/c-typeck.c
+@@ -5716,8 +5716,6 @@ build_c_cast (location_t loc, tree type, tree expr)
+   if (objc_is_object_ptr (type) && objc_is_object_ptr (TREE_TYPE (expr)))
+     return build1 (NOP_EXPR, type, expr);
+ 
+-  type = TYPE_MAIN_VARIANT (type);
+-
+   if (TREE_CODE (type) == ARRAY_TYPE)
+     {
+       error_at (loc, "cast specifies array type");