This issue now breaks gcc build:

`.LC2' referenced in section `.gnu.linkonce.t._ZN21mem_alloc_descriptionI9mem_us
ageED1Ev' of build/hash-table.o: defined in discarded section `.gnu.linkonce.r._
ZN10hash_tableIN8hash_mapIPKv14mem_usage_pairI9mem_usageE21simple_hashmap_traits
I19default_hash_traitsIS2_EEE10hash_entryE11xcallocatorE6expandEv.str1.4' of bui
ld/hash-table.o

This is with trunk revision 228461.  Occurs in stage2.

Re comment #2, this is with --disable-comdat added to configure command:

../gcc/configure --with-gnu-as --with-gnu-ld --enable-shared --enable-multiarch --enable-linker-build-id --build=hppa-linux-gnu --host=hppa-linux-gnu --target=hppa-linux-gnu --prefix=/home/dave/opt/gnu/gcc/gcc-6 --with-local-prefix=/home/dave/opt/gnu --disable-comdat --enable-threads=posix --enable-__cxa_atexit --build=hppa-linux-gnu --enable-clocale=gnu --enable-java-gc=boehm --enable-languages="c,c++,objc,fortran,obj-c++,java,ada,lto"

The ELF specification says "To facilitate removing a group without leaving dangling references and with only minimal processing of the symbol table, the following rules are followed.

    References to the sections comprising a group from sections outside of the group must be made through symbol table entries with STB_GLOBAL or STB_WEAK binding and section index SHN_UNDEF."

The label _ZN3uhd9transport3sphL19handle_overflow_nopEv is not globalized.

Probably, TREE_PUBLIC is not being set or there needs to be an addition
check added to assemble_start_function to globalize COMDAT functions.  Jason,
could you take a look?

I suppose this is a package bug but it is present in a number
of packages:

static inline void handle_overflow_nop(void){}

class recv_packet_handler{
public:
  ...
private:
    vrt_unpacker_type _vrt_unpacker;
    size_t _header_offset_words32;
    double _tick_rate, _samp_rate;
    bool _queue_error_for_next_call;
    size_t _alignment_faulure_threshold;
    rx_metadata_t _queue_metadata;
    struct xport_chan_props_type{
        xport_chan_props_type(void):
            packet_count(0),
            handle_overflow(&handle_overflow_nop),
            fc_update_window(0)
        {}
        get_buff_type get_buff;
        issue_stream_cmd_type issue_stream_cmd;
        size_t packet_count;
        handle_overflow_type handle_overflow;
        handle_flowctrl_type handle_flowctrl;
        size_t fc_update_window;
    };
    ...
};

Should there be a warning about a potential dangling reference?

GCC 5.3 is being released, adjusting target milestone.

GCC 5.4 is being released, adjusting target milestone.

The 5 branch has been closed, it is unclear what the state of this PR is on supported branches.

The test case now compiles successfully with 5.4.1 20171003 (Debian 5.4.1-14), g++-6 and g++-7.

This problem has reappeared since pa_reloc_rw_mask() was changed to allow relocs in readonly data.

See this binutils bugzilla:
https://sourceware.org/bugzilla/show_bug.cgi?id=25315

We have a plabel relocation to the local symbol __tcf_0 in a comdat section.

It is setup here:

start_cleanup_fn (void)
{
  char name[32];
  tree fntype;
  tree fndecl;
  bool use_cxa_atexit = flag_use_cxa_atexit
                        && !targetm.cxx.use_atexit_for_cxa_atexit ();

  push_to_top_level ();

  /* No need to mangle this.  */
  push_lang_context (lang_name_c);

  /* Build the name of the function.  */
  sprintf (name, "__tcf_%d", start_cleanup_cnt++);
  /* Build the function declaration.  */
  fntype = TREE_TYPE (get_atexit_fn_ptr_type ());
  fndecl = build_lang_decl (FUNCTION_DECL, get_identifier (name), fntype);
  /* It's a function with internal linkage, generated by the
     compiler.  */
  TREE_PUBLIC (fndecl) = 0;
  DECL_ARTIFICIAL (fndecl) = 1;
  /* Make the function `inline' so that it is only emitted if it is
     actually needed.  It is unlikely that it will be inlined, since
     it is only called via a function pointer, but we avoid unnecessary
     emissions this way.  */
  DECL_DECLARED_INLINE_P (fndecl) = 1;
  DECL_INTERFACE_KNOWN (fndecl) = 1;

The original problem was worked around with this binutils change:

static unsigned int
elf_hppa_action_discarded (asection *sec)
{
  /* Ignore relocations in .data.rel.ro.local.  This section can contain
     PLABEL32 relocations to functions in discarded COMDAT groups.  */
  if (strcmp (".data.rel.ro.local", sec->name) == 0)
    return 0;

Created attachment 47564 [details]
Patch

Untested fix.

Author: danglin
Date: Wed Jan  1 22:57:54 2020
New Revision: 279823

URL: https://gcc.gnu.org/viewcvs?rev=279823&root=gcc&view=rev
Log:
	PR target/67834
	* config/pa/pa.c (pa_elf_select_rtx_section): New.  Put references to
	COMDAT group function labels in .data.rel.ro.local section.
	* config/pa/pa32-linux.h (TARGET_ASM_SELECT_RTX_SECTION): Define.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/pa/pa.c
    trunk/gcc/config/pa/pa32-linux.h

Author: danglin
Date: Wed Jan  1 23:00:58 2020
New Revision: 279824

URL: https://gcc.gnu.org/viewcvs?rev=279824&root=gcc&view=rev
Log:
	PR target/67834
	* config/pa/pa.c (pa_elf_select_rtx_section): New.  Put references to
	COMDAT group function labels in .data.rel.ro.local section.
	* config/pa/pa32-linux.h (TARGET_ASM_SELECT_RTX_SECTION): Define.


Modified:
    branches/gcc-9-branch/gcc/ChangeLog
    branches/gcc-9-branch/gcc/config/pa/pa.c
    branches/gcc-9-branch/gcc/config/pa/pa32-linux.h

Resolved.