Currently, attribute "retain" is ignored since it avoids some
quirks in crtstuff -- which avr doesn't even use.
This renders attribute "used" pretty much useless: A function will
survive till asm, but without the "R" section flag, the linker
will kill the code with --gc-sections.
defaults.h requires .init_array without explaining why.
/* This determines whether or not we support marking sections with
SHF_GNU_RETAIN flag. Also require .init_array/.fini_array section
for constructors and destructors. */
#ifndef SUPPORTS_SHF_GNU_RETAIN
#if HAVE_GAS_SHF_GNU_RETAIN && HAVE_INITFINI_ARRAY_SUPPORT
#define SUPPORTS_SHF_GNU_RETAIN 1
#else
#define SUPPORTS_SHF_GNU_RETAIN 0
#endif
#endif
Bottom line is that SUPPORTS_SHF_GNU_RETAIN is defined to 0
since avr doesn't use .init_array.
This patch checks whether Binutils support the "R" flag, which
is provided by auto-host.h's HAVE_GAS_SHF_GNU_RETAIN.
If that's the case, avr/elf.h defines SUPPORTS_SHF_GNU_RETAIN to 1,
so that the code from defaults.h is bypassed (tm.h includes avr/elf.h
prior to defaults.h).
Passes without new regressions.
Ok to apply?
diff --git a/gcc/config/avr/elf.h b/gcc/config/avr/elf.h
index d240f8549d7..4520d84da6a 100644
--- a/gcc/config/avr/elf.h
+++ b/gcc/config/avr/elf.h
@@ -18,6 +18,19 @@
along with GCC; see the file COPYING3. If not see
<http://www.gnu.org/licenses/>. */
+/* defaults.h requires HAVE_INITFINI_ARRAY_SUPPORT to be present
+ in order for attribute "retain" to be recognized. This is due
+ to some quirks in crtstuff.h -- which isn't even used by avr.
+ All we need is that Binutils supports the "R"etain section flag.
+ If that's the case, define SUPPORTS_SHF_GNU_RETAIN so that
+ defaults.h doesn't define it to 0. */
+#if defined(IN_GCC) && !defined(USED_FOR_TARGET) &&
!defined(GENERATOR_FILE)
+#include "auto-host.h" /* HAVE_GAS_SHF_GNU_RETAIN */
+#if HAVE_GAS_SHF_GNU_RETAIN
+#undef SUPPORTS_SHF_GNU_RETAIN
+#define SUPPORTS_SHF_GNU_RETAIN 1
+#endif
+#endif
/* Overriding some definitions from elfos.h for AVR. */
