From 8ff34dbff1eac612326b492d0b2cb93901ad7e2b Mon Sep 17 00:00:00 2001
From: Jani Nurminen <jani.nurminen@windriver.com>
Date: Fri, 24 Sep 2021 09:56:11 +0200
Subject: [PATCH] Lower init prio for extension attributes
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Added PROTOBUF_EXTENSION_ATTRIBUTE_INIT_PRIORITY in
code generation for extension attributes.
It has lower prio than PROTOBUF_ATTRIBUTE_INIT_PRIORITY to
ensure that extension attributes are initialized after
other attribute.
This is needed in some applications to avoid segmentation fault.

Reported by Karl-Herman Näslund.

Signed-off-by: Jani Nurminen <jani.nurminen@windriver.com>

Rebase on master

Signed-off-by: He Zhe <zhe.he@windriver.com>
---
 src/google/protobuf/compiler/cpp/cpp_extension.cc |  2 +-
 src/google/protobuf/port_def.inc                  | 12 ++++++++++++
 src/google/protobuf/port_undef.inc                |  1 +
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/google/protobuf/compiler/cpp/cpp_extension.cc b/src/google/protobuf/compiler/cpp/cpp_extension.cc
index 8604da5f2..984345ebe 100644
--- a/src/google/protobuf/compiler/cpp/cpp_extension.cc
+++ b/src/google/protobuf/compiler/cpp/cpp_extension.cc
@@ -164,7 +164,7 @@ void ExtensionGenerator::GenerateDefinition(io::Printer* printer) {
   }
 
   format(
-      "PROTOBUF_ATTRIBUTE_INIT_PRIORITY "
+      "PROTOBUF_EXTENSION_ATTRIBUTE_INIT_PRIORITY "
       "::$proto_ns$::internal::ExtensionIdentifier< $extendee$,\n"
       "    ::$proto_ns$::internal::$type_traits$, $field_type$, $packed$ >\n"
       "  $scoped_name$($constant_name$, $1$);\n",
diff --git a/src/google/protobuf/port_def.inc b/src/google/protobuf/port_def.inc
index 7e9119112..a5117090d 100644
--- a/src/google/protobuf/port_def.inc
+++ b/src/google/protobuf/port_def.inc
@@ -614,6 +614,18 @@
 #define PROTOBUF_ATTRIBUTE_INIT_PRIORITY
 #endif
 
+// Some embedded systems get a segmentation fault if extension attributes are
+// initialized with higher or equal priority as other attributes. This gives
+// extension attributes high priority, but lower than other attributes.
+#ifdef PROTOBUF_EXTENSION_ATTRIBUTE_INIT_PRIORITY
+#error PROTOBUF_EXTENSION_ATTRIBUTE_INIT_PRIORITY was previously defined
+#endif
+#if PROTOBUF_GNUC_MIN(3, 0) && (!defined(__APPLE__) || defined(__clang__)) && !((defined(sun) || defined(__sun)) && (defined(__SVR4) || defined(__svr4__)))
+#define PROTOBUF_EXTENSION_ATTRIBUTE_INIT_PRIORITY __attribute__((init_priority((103))))
+#else
+#define PROTOBUF_EXTENSION_ATTRIBUTE_INIT_PRIORITY
+#endif
+
 #ifdef PROTOBUF_PRAGMA_INIT_SEG
 #error PROTOBUF_PRAGMA_INIT_SEG was previously defined
 #endif
diff --git a/src/google/protobuf/port_undef.inc b/src/google/protobuf/port_undef.inc
index ccc5daf56..2b28f3a31 100644
--- a/src/google/protobuf/port_undef.inc
+++ b/src/google/protobuf/port_undef.inc
@@ -83,6 +83,7 @@
 #undef PROTOBUF_HAVE_ATTRIBUTE_WEAK
 #undef PROTOBUF_ATTRIBUTE_NO_DESTROY
 #undef PROTOBUF_ATTRIBUTE_INIT_PRIORITY
+#undef PROTOBUF_EXTENSION_ATTRIBUTE_INIT_PRIORITY
 #undef PROTOBUF_PRAGMA_INIT_SEG
 #undef PROTOBUF_ASAN
 #undef PROTOBUF_MSAN
-- 
2.26.2

