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Differences in GCC and ICC compiled objects, GCC relocations broken?
- From: J K <jkwipub at gmail dot com>
- To: gcc at gcc dot gnu dot org
- Date: Thu, 23 Feb 2012 10:31:21 -0500
- Subject: Differences in GCC and ICC compiled objects, GCC relocations broken?
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?Posted in the Intel forums but this may be more of a GCC issue.
Please advise if I should post elsewhere.
?Compiling a C module in with a large app (>2GB data) and getting
relocatable errors with GCC and
not ICC.
./classification_dpr_BB.o: In function `BB_detection_dpr':
/homedata/johnk/dpr/src_
20120126/DD2_V2.20120126/src/./
classification_dpr_BB.c:118: relocation truncated to fit:
R_X86_64_PC32 against `.bss'
?Can anyone familiar with the output of readelf see why the GCC
?object is not relocatable and the ICC one is? Would another tool
?be more suitable?
icc -I../include -g -v -sox -fPIC -mcmodel=medium -DDEBUG ?-c
./classification_dpr_BB.c
cc -I../include -g -v -fPIC -mcmodel=medium -DDEBUG ?-c
./classification_dpr_BB.c
? This module does not use more than 2GB data itself, I just need it
to be linked with
? code that does, so -fPIC. ?I left off the medium memory model switch
on both with no impact.
? Everything is static except for the -shared-intel -mcmodel=medium
on the main link (ifort is used).
? Could it have something to do with the relocation types? Are there
switches to GCC to force relocations
like ICC?
GCC
Relocation section '.rela.text' at offset 0xd040 contains 449 entries:
?Offset ? ? ? ? ?Info ? ? ? ? ? Type ? ? ? ? ? Sym. Value ? ?Sym.
Name + Addend
00000000004e ?001700000002 R_X86_64_PC32 ? ? 0000000000000000 .rodata
+ fffffffffffffffc
00000000008e ?000400000002 R_X86_64_PC32 ? ? 0000000000000000 .bss +
1e5c
0000000000bc ?000400000002 R_X86_64_PC32 ? ? 0000000000000000 .bss +
105c
ICC
Relocation section '.rela.text' at offset 0xf222 contains 732 entries:
?Offset ? ? ? ? ?Info ? ? ? ? ? Type ? ? ? ? ? Sym. Value ? ?Sym.
Name + Addend
000000000030 ?00780000001a R_X86_64_GOTPC32 ?0000000000000000
_GLOBAL_OFFSET_TABLE_ + fffffffffffffffc
000000000036 ?000600000019 R_X86_64_GOTOFF64 0000000000000000
_2il0floatpacket.15 + 0
000000000057 ?000700000019 R_X86_64_GOTOFF64 0000000000000008
_2il0floatpacket.16 + 0
00000000009f ?00780000001a R_X86_64_GOTPC32 ?0000000000000000
_GLOBAL_OFFSET_TABLE_ + fffffffffffffffc
gcc (GCC) 4.1.2 20080704 (Red Hat 4.1.2-51)
icc (ICC) 11.1 20100806
?The full output of readelf -all are at these links.
ICC
http://www.box.com/s/2iqnqydmi0mdz52xs9ac
GCC
http://www.box.com/s/jjcgq1x2s5ybpg7s9b6g
Thanks for any help.