Possible bug in gas/ld when using .linkonce

[Pavel Tsekov <ptsekov at gmx dot net>]

Hello,

I found this one while playing with Cygwin's code which takes care of
seamless loading of dll functions (autoload.cc). It seems that when a
symbol in a section marked .linkonce is referenced, wrong relocation info
is generated for that symbol.

For example if you have several symbols - symbol1, symbol2 and symbol3,
- which are placed like this:

offset name
     0 symbol1
     3 symbol2
    15 symbol3

References to this symbols will be generated like this:

symbol1 -> 0
symbol2 -> 6
symbol3 -> 30

I am attaching a testcase. linkonce.cc is the code which demonstrates the
problem. linkonce1.cc is the same code but with .linkonce directives
removed and doesn't suffer from the problem. Here is also the output of
`objdump -r' on both object files.

$ g++ -o linkonce.o -c linkonce.cc
$ objdump -r linkonce.o

linkonce.o:     file format pe-i386

RELOCATION RECORDS FOR [.text]:
OFFSET   TYPE              VALUE
00000015 DISP32            __alloca
0000001a DISP32            ___main


RELOCATION RECORDS FOR [.some_section1_text]:
OFFSET   TYPE              VALUE
00000001 dir32             .some_section1_text
00000007 dir32             _label_1


RELOCATION RECORDS FOR [.some_section2_text]:
OFFSET   TYPE              VALUE
00000001 dir32             .some_section2_text
00000007 dir32             _label_2+0xffffffee


RELOCATION RECORDS FOR [.some_section3_text]:
OFFSET   TYPE              VALUE
00000001 dir32             .some_section3_text
00000007 dir32             _label_3+0xffffffe3

$ g++ -o linkonce1.o -c linkonce1.cc
$ objdump -r linkonce1.o

linkonce1.o:     file format pe-i386

RELOCATION RECORDS FOR [.text]:
OFFSET   TYPE              VALUE
00000015 DISP32            __alloca
0000001a DISP32            ___main


RELOCATION RECORDS FOR [.some_section1_text]:
OFFSET   TYPE              VALUE
00000001 dir32             .some_section1_text
00000007 dir32             .some_section


RELOCATION RECORDS FOR [.some_section2_text]:
OFFSET   TYPE              VALUE
00000001 dir32             .some_section2_text
00000007 dir32             .some_section


RELOCATION RECORDS FOR [.some_section3_text]:
OFFSET   TYPE              VALUE
00000001 dir32             .some_section3_text
00000007 dir32             .some_section

Attachment: linkonce1.cc
Description: Text document

Attachment: linkonce.cc
Description: Text document