[Bug target/48096] gcc.dg/tree-prof/bb-reorg.c compilation, -fprofile-use -D_PROFILE_USE fails with Xcode 4.0

["howarth at nitro dot med.uc.edu" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48096

--- Comment #6 from Jack Howarth <howarth at nitro dot med.uc.edu> 2011-03-17 23:41:29 UTC ---
The darwin linker developer says...
----------------------------------------------------------------------------
The issue is in the __eh_frame, the reloc for second FDE's pointer to its
function (__cold_sect_of_foo) is bad:

otool -rv bb-reorg.o

Relocation information (__TEXT,__eh_frame) 6 entries
address  pcrel length extern type    scattered symbolnum/value
00000060 False quad   True   SUB     False     EH_frame1
00000060 False quad   True   UNSIGND False     _main
00000040 False quad   True   SUB     False     EH_frame1
00000040 False quad   False  UNSIGND False     2 (__TEXT,__text_cold)
00000020 False quad   True   SUB     False     EH_frame1
00000020 False quad   True   UNSIGND False     _foo

The local relocation at 0x40 should be an external relocation just like it is
for _foo and _main.

The pair of relocs SUB/UNSIGNED need to point to non-local labels.  What does
the assembly look like in the FDE?  Is it  different that in the FDE for main
and foo?
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I see you added the .s file too.

It currently starts with:

        .section __TEXT,__text_cold
LCOLDB0:
        .text
...

       .section __TEXT,__text_cold
__cold_sect_of_foo:


If I move the LCOLDB0 label down to be right after the __cold_sect_of_foo
label, then it compiles and links fine.  I think this is an assembler bug, but
the compiler  work around should be easy enough:  Either use the real label
name (e.g. __cold_sect_of_foo) in the FDE, or but L label that is supposed to
be equivalent to it after the real label.