interpreting gcc map file

Question

I need to find the code size for a library developed using C on linux. I have generated the map file using the gcc linker options against a sample application that uses this library.

The map file is quite exhaustive. How do I find out the code size of the library from the map file? any pointers to any documentation on how to interpret the map file would also be very useful.

Answer 1

You want to find out the size of the machine instructions in a given shared object? Why do you need the map file?

This gives the size of the .text section. The .text section is where executable code is stored:

$ objdump  -x /usr/bin/objdump | grep .text
 13 .text         0002c218  0000000000403320  0000000000403320  00003320  2**4

In this example, there are 2c218 bytes of executable text. In decimal this is about 180 KiB:

$ printf %d\\n 0x2c218
180760

Edit: This is how it looks like with a library:

$ objdump -x /usr/lib/libcairo.so | grep .text
 11 .text         00054c18  000000000000cc80  000000000000cc80  0000cc80  2**4
$ printf %d\\n 0x54c18
347160