How to measure the code (i.e. data + text) size of a static library?

Question

I've looked on SO for an answer to this, but didn't find one. I have a large static library - it still has all its symbols so its huge. What I'd like to know is what the actual code size it consumes when linked into an app and stripped.

The library also all current architectures lipoed into it, so really what I need is the code (i.e. data + text) for each architecture.

score 8 · Accepted Answer · edited May 23 '17 at 10:34

I posted this originally because I was curious, but a client really wanted to know today so I had to dig. Turns out that there is a CLI command size that can help:

$ size  -arch arm64 myLib.a
__TEXT    __DATA    __OBJC    others    dec    hex
18436    7156    0    42642    68234    10a8a    myLib.a(a.o)
1659      528    0    7209      9396     24b4    myLib.a(b.o)
...

Wow - that "others" looks really huge. Wonder what's in it? Hmmm, try the -m option, and you get a really long output of each file in the library, and the size of each segment in the library.

When I use the -m option on my library, I get a slew of segments with prefix names of "__debug":

myLib.a(a.o):
Segment : 47665
    Section (__TEXT, __text): 9832
    Section (__DWARF, __debug_info): 9625
    Section (__DWARF, __debug_abbrev): 867
    Section (__DWARF, __debug_aranges): 64
    Section (__DWARF, __debug_macinfo): 0
    Section (__DWARF, __debug_line): 2142
    Section (__DWARF, __debug_loc): 7237
    Section (__DWARF, __debug_str): 4750
    Section (__DWARF, __debug_ranges): 240
    Section (__DATA, __data): 0
    Section (__TEXT, __literal8): 16
    ...
    Section (__DWARF, __apple_names): 2364
    Section (__DWARF, __apple_objc): 196
    Section (__DWARF, __apple_namespac): 36
    Section (__DWARF, __apple_types): 1924
total 47652
 total 47665

To get a value of what this code will consume when stripped in the final app, I need to get the full segment size and subtract out the size of all the "__debug" prefixed segments.

# Get the full size of all object files in the library
$ size -m -arch arm64 *.a | grep '^.total' | sed -n -e 's/^.total //p' | awk '{s+=$1} END {print s}'
381423
$

# Get the size of the debugging sections:
$ size  -m -arch arm64 *.a | grep __debug_ | sed -n -e 's/^.*: //p' | awk '{s+=$1} END {print s}'
212702
$

The total is thus 381423 - 212702 = 168721 # more or less

PS: awk script from This SO post

How to measure the code (i.e. data + text) size of a static library?

1 Answers1