8sa1-gcc/gcc/testsuite/c-c++-common/attr-used-9.c
H.J. Lu 6347f4a090 Add retain attribute to place symbols in SHF_GNU_RETAIN section
When building Linux kernel, ld in bninutils 2.36 with GCC 11 generates
thousands of

ld: warning: orphan section `.data.event_initcall_finish' from `init/main.o' being placed in section `.data.event_initcall_finish'
ld: warning: orphan section `.data.event_initcall_start' from `init/main.o' being placed in section `.data.event_initcall_start'
ld: warning: orphan section `.data.event_initcall_level' from `init/main.o' being placed in section `.data.event_initcall_level'

Since these sections are marked with SHF_GNU_RETAIN, they are placed in
separate sections.  They become orphan sections since they aren't expected
in the Linux kernel linker script. But orphan sections normally don't work
well with the Linux kernel linker script and the resulting kernel crashed.

Add the "retain" attribute to place symbols in separate SHF_GNU_RETAIN
sections.  Issue a warning if the configured assembler/linker doesn't
support SHF_GNU_RETAIN.

gcc/

	PR target/99113
	* varasm.c (get_section): Replace SUPPORTS_SHF_GNU_RETAIN with
	looking up the retain attribute.
	(resolve_unique_section): Likewise.
	(get_variable_section): Likewise.
	(switch_to_section): Likewise.  Warn when a symbol without the
	retain attribute and a symbol with the retain attribute are
	placed in the section with the same name, instead of the used
	attribute.
	* doc/extend.texi: Document the "retain" attribute.

gcc/c-family/

	PR target/99113
	* c-attribs.c (c_common_attribute_table): Add the "retain"
	attribute.
	(handle_retain_attribute): New function.

gcc/testsuite/

	PR target/99113
	* c-c++-common/attr-retain-1.c: New test.
	* c-c++-common/attr-retain-2.c: Likewise.
	* c-c++-common/attr-retain-3.c: Likewise.
	* c-c++-common/attr-retain-4.c: Likewise.
	* c-c++-common/attr-retain-5.c: Likewise.
	* c-c++-common/attr-retain-6.c: Likewise.
	* c-c++-common/attr-retain-7.c: Likewise.
	* c-c++-common/attr-retain-8.c: Likewise.
	* c-c++-common/attr-retain-9.c: Likewise.
	* c-c++-common/pr99113.c: Likewise.
	* gcc.c-torture/compile/attr-retain-1.c: Likewise.
	* gcc.c-torture/compile/attr-retain-2.c: Likewise.
	* c-c++-common/attr-used.c: Don't expect SHF_GNU_RETAIN section.
	* c-c++-common/attr-used-2.c: Likewise.
	* c-c++-common/attr-used-3.c: Likewise.
	* c-c++-common/attr-used-4.c: Likewise.
	* c-c++-common/attr-used-9.c: Likewise.
	* gcc.c-torture/compile/attr-used-retain-1.c: Likewise.
	* gcc.c-torture/compile/attr-used-retain-2.c: Likewise.
	* c-c++-common/attr-used-5.c: Don't expect warning for the used
	attribute nor SHF_GNU_RETAIN section.
	* c-c++-common/attr-used-6.c: Likewise.
	* c-c++-common/attr-used-7.c: Likewise.
	* c-c++-common/attr-used-8.c: Likewise.
2021-02-18 13:27:38 -08:00

30 lines
833 B
C

/* { dg-do compile } */
/* { dg-skip-if "non-ELF target" { *-*-darwin* } } */
/* { dg-options "-Wall -O2" } */
struct dtv_slotinfo_list
{
struct dtv_slotinfo_list *next;
};
extern struct dtv_slotinfo_list *list;
static int __attribute__ ((used, section ("__libc_freeres_fn")))
free_slotinfo (struct dtv_slotinfo_list **elemp)
{
if (!free_slotinfo (&(*elemp)->next))
return 0;
return 1;
}
__attribute__ ((section ("__libc_freeres_fn")))
static void free_mem (void)
/* { dg-warning "defined but not used" "" { target *-*-* } .-1 } */
{
free_slotinfo (&list);
}
/* { dg-final { scan-assembler-not "__libc_freeres_fn\n" } } */
/* { dg-final { scan-assembler "__libc_freeres_fn,\"ax\"" { target R_flag_in_section } } } */
/* { dg-final { scan-assembler-not "__libc_freeres_fn,\"axR\"" { target R_flag_in_section } } } */