[llvm] r185882 - Don't run internalize if we're outputing bit-code and not an object file.

[Rafael Espíndola]

> The linker already does tell LTO to preserve all global symbols in -r mode.
>
> Given that the original bug involved linker private symbols  (start with
> ‘l’), I made a test case of all combinations of weak, hidden, and linker
> private.  I did notice that the merging of bit code files happens as if the
> -keep_private_externs were used, but that should not matter.
>
> Was does seem to be the problem is that the weak bit is lost on
> _weak_hidden_glob and l_weak_hidden_special.

Interesting. This seems to work on ELF:

$ cat test.c
__attribute__((weak, visibility("hidden")))
void weak_hidden_glob() { }
$ clang -c test.c -flto
$ ld --plugin /home/espindola/inst/clang/lib/LLVMgold.so -r test.o -o test-r.o
$ readelf  -sW test-r.o

Symbol table '.symtab' contains 4 entries:
   Num:    Value          Size Type    Bind   Vis      Ndx Name
     0: 0000000000000000     0 NOTYPE  LOCAL  DEFAULT  UND
     1: 0000000000000000     0 SECTION LOCAL  DEFAULT    5
     2: 0000000000000000     0 FILE    LOCAL  DEFAULT  ABS ld-temp.o
     3: 0000000000000000     6 FUNC    WEAK   HIDDEN     5 weak_hidden_glob

$ ld --plugin /home/espindola/inst/clang/lib/LLVMgold.so -r test.o
-plugin-opt emit-llvm -o test-r.o
$ llvm-dis test-r.o -o -  | grep weak_hi
define weak hidden void @weak_hidden_glob() #0 {

Cheers,
Rafael