Easy to read Golang assembly output?

Question

I\'m interested in examining the x86 assembly output of the standard Go compiler to see if my code is really being converted into reasonably efficient assembly code; hopeful

Answer 1

To dump the output to file:

go tool objdump EXECUTABLE_FILE > ASSEMBLY_FILE

If you want to include the source Go code (assuming you have a working golang setup, and you built the executable yourself):

go tool objdump -S EXECUTABLE_FILE

To make the output even easier to look at I use a small hacky wrapper that produces the following (in a nutshell, it colorizes instructions that alter the control flow -blue for jumps, green for call/return, red for traps, violet for padding- and adds new lines after unconditional control flow jumps):

If you use the wrapper above you will likely want to use the -R switch when piping to less (or by adding it to the environment, e.g. in .bashrc: export LESS="$LESS -R"):

go-objdump EXECUTABLE_FILE | less -R

Alternatively, there is godbolt.org that has probably the most readable output and allows you to switch between compilers (gc, gccgo) and versions very easily.