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One method for checking symbol alignment on macOS for a mach-O object file is to use the "nm" command in the terminal. The "nm" command displays the symbols (i.e. function names, variable names) and their corresponding addresses in the object file. To check the alignment, you would need to look at the last digit(s) of the addresses.

For example, to check the symbol alignment of an object file called "myobject.o", you could enter the following command in the terminal:

nm -n myobject.o

The "-n" option sorts the output by symbol name, and the "-v" option displays the addresses in hexadecimal format. The last digit(s) of the addresses represent the alignment, where a "0" indicates the symbol is aligned on a 16-byte boundary, "1" indicates it is aligned on an 8-byte boundary, "2" indicates it is aligned on a 4-byte boundary, and so on.

You can also use the "otool" command to display the same information in a slightly different format:

otool -v -t myobject.o

This command displays the sections of the object file and the symbols within each section, along with their addresses, alignment, and other information. The alignment is shown in the "n_desc" column, where the value represents the alignment minus 1. Therefore, a value of "0" indicates a 16-byte alignment, "1" indicates 8-byte alignment, and so on.