From: Longjun Luo <luolongjuna@gmail.com>
To: gcc-patches@gcc.gnu.org
Cc: luolongjuna@gmail.com, sangyan@huawei.com
Subject: [PATCH] libcpp: suppress builtin macro redefined warnings for __LINE__
Date: Thu, 1 Dec 2022 12:31:55 +0800 [thread overview]
Message-ID: <20221201043155.9369-1-luolongjuna@gmail.com> (raw)
As implied in
gcc.gnu.org/legacy-ml/gcc-patches/2008-09/msg00076.html,
gcc provides -Wno-builtin-macro-redefined to suppress warning when
redefining builtin macro. However, at that time, there was no
scenario for __LINE__ macro.
But, when we try to build a live-patch, we compare sections by using
-ffunction-sections. Some same functions are considered changed because
of __LINE__ macro.
At present, to detect such a changed caused by __LINE__ macro, we
have to analyse code and maintain a function list. For example,
in kpatch, check this commit
github.com/dynup/kpatch/commit/0e1b95edeafa36edb7bcf11da6d1c00f76d7e03d.
So, in this scenario, when we try to compared sections, it would
be better to support suppress builtin macro redefined warnings for
__LINE__ macro.
Signed-off-by: Longjun Luo <luolongjuna@gmail.com>
---
gcc/testsuite/gcc.dg/builtin-redefine.c | 1 -
libcpp/init.cc | 2 +-
2 files changed, 1 insertion(+), 2 deletions(-)
diff --git a/gcc/testsuite/gcc.dg/builtin-redefine.c b/gcc/testsuite/gcc.dg/builtin-redefine.c
index 882b2210992..9d5b42252ee 100644
--- a/gcc/testsuite/gcc.dg/builtin-redefine.c
+++ b/gcc/testsuite/gcc.dg/builtin-redefine.c
@@ -71,7 +71,6 @@
/* { dg-bogus "Expected built-in is not defined" "" { target *-*-* } .-1 } */
#endif
-#define __LINE__ 0 /* { dg-warning "-:\"__LINE__\" redef" } */
#define __INCLUDE_LEVEL__ 0 /* { dg-warning "-:\"__INCLUDE_LEVEL__\" redef" } */
#define __COUNTER__ 0 /* { dg-warning "-:\"__COUNTER__\" redef" } */
diff --git a/libcpp/init.cc b/libcpp/init.cc
index 5f34e3515d2..2765b9838b7 100644
--- a/libcpp/init.cc
+++ b/libcpp/init.cc
@@ -421,7 +421,7 @@ static const struct builtin_macro builtin_array[] =
B("__FILE__", BT_FILE, false),
B("__FILE_NAME__", BT_FILE_NAME, false),
B("__BASE_FILE__", BT_BASE_FILE, false),
- B("__LINE__", BT_SPECLINE, true),
+ B("__LINE__", BT_SPECLINE, false),
B("__INCLUDE_LEVEL__", BT_INCLUDE_LEVEL, true),
B("__COUNTER__", BT_COUNTER, true),
/* Make sure to update the list of built-in
--
2.38.1
next reply other threads:[~2022-12-01 4:32 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-01 4:31 Longjun Luo [this message]
2022-12-01 17:01 ` Joseph Myers
2022-12-01 18:23 ` Longjun Luo
2022-12-01 19:07 ` Joseph Myers
2022-12-01 19:51 ` Longjun Luo
2022-12-01 21:10 ` Joseph Myers
2023-01-12 16:02 ` Longjun Luo
2023-04-30 18:30 ` Jeff Law
2023-04-30 23:14 ` Jeff Law
2023-04-30 23:19 ` Andrew Pinski
2023-01-12 16:05 ` Longjun Luo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20221201043155.9369-1-luolongjuna@gmail.com \
--to=luolongjuna@gmail.com \
--cc=gcc-patches@gcc.gnu.org \
--cc=sangyan@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).