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authorFangrui Song <maskray@google.com>2021-04-16 11:26:39 -0700
committerFangrui Song <maskray@google.com>2021-04-16 11:26:39 -0700
commitcd6ae7ea5431c2b8f16201fb0e2c413bf8d2df06 (patch)
tree68d5b5402097696b3e3898fad40a143720da0438 /config.h.in
parent1a8605b6cd257e8a74e29b5b71c057211f5fb847 (diff)
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Set the retain attribute on _elf_set_element if CC supports [BZ #27492]
So that text_set_element/data_set_element/bss_set_element defined variables will be retained by the linker. Note: 'used' and 'retain' are orthogonal: 'used' makes sure the variable will not be optimized out; 'retain' prevents section garbage collection if the linker support SHF_GNU_RETAIN. GNU ld 2.37 and LLD 13 will support -z start-stop-gc which allow C identifier name sections to be GCed even if there are live __start_/__stop_ references. Without the change, there are some static linking problems, e.g. _IO_cleanup (libio/genops.c) may be discarded by ld --gc-sections, so stdout is not flushed on exit. Note: GCC may warning 'retain' attribute ignored while __has_attribute(retain) is 1 (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99587). Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Diffstat (limited to 'config.h.in')
-rw-r--r--config.h.in3
1 files changed, 3 insertions, 0 deletions
diff --git a/config.h.in b/config.h.in
index ca1547ae67..96a08c7757 100644
--- a/config.h.in
+++ b/config.h.in
@@ -187,6 +187,9 @@
/* Define if gcc supports attribute ifunc. */
#undef HAVE_GCC_IFUNC
+/* Define if CC supports attribute retain. */
+#undef HAVE_GNU_RETAIN
+
/* Define if the linker defines __ehdr_start. */
#undef HAVE_EHDR_START