diff options
| author | Fangrui Song <i@maskray.me> | 2021-03-28 23:35:06 -0700 |
|---|---|---|
| committer | Zbigniew Jędrzejewski-Szmek <zbyszek@in.waw.pl> | 2021-03-29 12:31:42 +0200 |
| commit | 945317a4b69d33752c9513bb8994fe8d5a786ea6 (patch) | |
| tree | 8efd1da75ac11277d9bd7e924ba560c420000d33 | |
| parent | 8a773a30ba622faf62e4313b0add25808a2b4df9 (diff) | |
| download | systemd-945317a4b69d33752c9513bb8994fe8d5a786ea6.tar.gz | |
sd-bus: set retain attribute on BUS_ERROR_MAP_ELF_REGISTER
LLD 13 and GNU ld 2.37 support -z start-stop-gc which allows garbage
collection of C identifier name sections despite the __start_/__stop_
references. Simply set the retain attribute so that GCC 11 (if
configure-time binutils is 2.36 or newer)/Clang 13 will set the
SHF_GNU_RETAIN section attribute to prevent garbage collection.
Without the patch, there are linker errors like the following with -z
start-stop-gc.
```
ld: error: undefined symbol: __start_SYSTEMD_BUS_ERROR_MAP
>>> referenced by bus-error.c:93 (../src/libsystemd/sd-bus/bus-error.c:93)
>>> sd-bus_bus-error.c.o:(bus_error_name_to_errno) in archive src/libsystemd/libsystemd_static.a
```
| -rw-r--r-- | src/libsystemd/sd-bus/bus-error.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/src/libsystemd/sd-bus/bus-error.h b/src/libsystemd/sd-bus/bus-error.h index 557284faf8..d981f72449 100644 --- a/src/libsystemd/sd-bus/bus-error.h +++ b/src/libsystemd/sd-bus/bus-error.h @@ -28,11 +28,17 @@ int bus_error_set_errnofv(sd_bus_error *e, int error, const char *format, va_lis * the bus error table, and BUS_ERROR_MAP_ELF_USE has to be used at * least once per compilation unit (i.e. per library), to ensure that * the error map is really added to the final binary. + * + * In addition, set the retain attribute so that the section cannot be + * discarded by ld --gc-sections -z start-stop-gc. Older compilers would + * warn for the unknown attribute, so just disable -Wattributes. */ #define BUS_ERROR_MAP_ELF_REGISTER \ + _Pragma("GCC diagnostic ignored \"-Wattributes\"") \ _section_("SYSTEMD_BUS_ERROR_MAP") \ _used_ \ + __attribute__((retain)) \ _alignptr_ \ _variable_no_sanitize_address_ |