[llvm-dev] LLD : __start_ and __end_ symbols for orphan sections

[Moshtaghi, Alireza via llvm-dev]

Sorry for the cryptic code but I had to modify stuff from original
In the following example see the difference when you comment or uncomment the line in the linker script:
============ test.c ============= :
struct orphan_dummy_anno_s {
 void (*func)(void);
};

static void dummy_export_dbg_log_init_f (void) __attribute__ ((unused));
static struct orphan_dummy_anno_s const
  dummy_export_dbg_log_init_linker_set =
  { dummy_export_dbg_log_init_f, };
__asm__ (".globl " "__start_set_orphan_dummy_anno");
__asm__ (".globl " "__stop_set_orphan_dummy_anno");
static void const
  *__set_orphan_dummy_anno_sym_dummy_export_dbg_log_init_linker_set
  __attribute__ ((__section__ ("set_" "orphan_dummy_anno")))
  __attribute__ ((__used__)) = &dummy_export_dbg_log_init_linker_set;
============ linker_script ============= :
SECTIONS {
   data : { *(data) }
# when commented, the __start and __stop symbols will be protected. How can I keep it from setting it as protected?
#   set_orphan_dummy_anno : { PROVIDE(__start_set_orphan_dummy_anno = . ); *(set_orphan_dummy_anno) PROVIDE (__stop_set_orphan_dummy_anno = . );}
}
============ howto ============= :
LDFLAGS="-Bshareable -T ./linker_script"
clang -fPIC -c test.c
ld.lld $LDFLAGS test.o -o test.so
objdump -tT test.so


On 6/2/20, 12:00 AM, "llvm-dev on behalf of Moshtaghi, Alireza via llvm-dev" <llvm-dev-bounces at lists.llvm.org on behalf of llvm-dev at lists.llvm.org> wrote:

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    You are right it creates them but sets the protected flag (STV_PROTECTED) which seems to be the cause of my problem.
    How can I tell it to set the flag as STV_DEFAULT?

    Thanks
    A

    On 5/28/20, 11:30 PM, "Fangrui Song" <maskray at google.com> wrote:

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        On 2020-05-28, Moshtaghi, Alireza via llvm-dev wrote:
        >lld does not seem to create the __start and __end symbols for orphan sections.
        >I would like to keep my linker script as generic as possible so how can I tell lld to create these symbols without having to add them in the linker script?
        >
        >Thanks
        >A

        It works for me.

        SECTIONS {
           data : { *(data) }
        }

        .section data,"aw"
        .quad __start_orphan
        .quad __stop_orphan

        .section orphan,"aw"
        .quad __start_data
        .quad __stop_data


        Can you give an example __start_ or __end_ symbols are not defined for orphan sections?

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