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readelf/objdump segment size doesn't match symbol table sizes
- From: showard <showard at cs dot clemson dot edu>
- To: binutils at sourceware dot org
- Date: Thu, 10 Aug 2006 12:19:16 -0700 (PDT)
- Subject: readelf/objdump segment size doesn't match symbol table sizes
I am sorry about the length of this post, but my problem takes a good bit of
I am using msp430-readelf and msp430-objdump to get information about the
sizes of functions and global variables from the executable generated by
compiling a tinyOS application. But, I am having trouble reconciling the
segment sizes (.text, .bss, and .data) reported by readelf and objdump with
the sizes of the individual objects as reported by 'readelf -s'
For example, I have an executable called 'main.exe'. objdump and readelf
both report the following segment sizes:
when I have readelf display the symbol table entries with 'msp430-readelf -s
main.exe', I get something like this fragment below. A '1' in the 'Ndx'
column indicates that this belongs to the .text section while '2' and '6'
indicate .data and .bss sections, respectively.
Symbol table '.symtab' contains 336 entries:
Num: Value Size Type Bind Vis Ndx Name
255: 00004e3e 76 FUNC LOCAL DEFAULT 1
256: 00001104 2 OBJECT LOCAL DEFAULT 6 i.0
257: 00001102 2 OBJECT LOCAL DEFAULT 2 sum.1
258: 00001106 2 OBJECT LOCAL DEFAULT 6 sum.2
259: 0000547e 182 FUNC LOCAL DEFAULT 1 SenseTaskM$display
260: 00004e8a 14 FUNC LOCAL DEFAULT 1
261: 0000556a 272 FUNC LOCAL DEFAULT 1
262: 00005778 24 FUNC LOCAL DEFAULT 1
263: 00005790 24 FUNC LOCAL DEFAULT 1
264: 00000000 0 FILE LOCAL DEFAULT ABS
265: 00001108 1 OBJECT GLOBAL DEFAULT 6 SenseTaskM$head
266: 0000110a 2 OBJECT GLOBAL DEFAULT 6
267: 0000110c 24 OBJECT GLOBAL DEFAULT 6 TimerM$m_timers
When I sum the numbers in the 'size' column that also have a '1' in the
'Ndx' column, I get 5960 instead of 6060. Also, when I sum the 'size' column
figures that have a '2' in the 'Ndx' column, I get 3 instead of 4, and for
the 'Ndx' column value of '6', I get 112 instead of 116.
I have generated these sums automatically using a simple program I wrote
and, to verify the values, I summed them by hand. In both cases, I got the
same values. This seems to say that there is "stuff" in these sections that
contribute to the size which is not in the symbol table. But, I can't find
any information about this anywhere. However, for some applications, some of
the values match.
Does anybody have any idea why these figures don't match???
I don't think that the fact that I am working with tinyOS and nesC is
important, but I mention it just in case.
Thanks for any help that can be provided!
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