sir-ragna / popularity-contest

See which x86_64 instructions are the most popular in your ELF files.

What is the most popular instruction?

That is the question that I wanted to answer.

You can run it on an x64 ELF files and it will read out the .text section and count the instructions, writing the results to stdout in comma-separated format.

[popularity-contest]$ ./main /usr/bin/ls /usr/bin/bash 2>/dev/null 
*filename*,setnz,addt,test,test,sbbt,andt,subt,xort,cmpt,rol,ror,shl,shr,sar,test,not,neg,mul,imul,div,idiv,call,jmp,push,jo,jno,jb,jnb,jz,jnz,jbe,ja,js,jns,jp,jl,jge,jle,jg,fadd,fmul,fsubr,fld,fstp,fldcw,fnstcw,ret,fldz,fild,fistp,fucomi,fcomi,fmulp,fdivpp,hlt,ud2,cmovb,cmovnb,cmovz,cmovnz,cmovbe,cmova,cmovs,cmovns,cmovl,cmovge,cmovle,cmovg,bt,btc,bt,cqo,pxor,bswap,addss,mulss,subss,divss,addsd,mulsd,fcomip,divsd,cdq,cdqe,cvtsi2sd,cvtsi2ss,cvttss2si,movaps,comiss,lea,mov,movdqa,movdqu,rep,rep,movsx,movsxd,movzx,nop,pop,rep,fxch,fucomip,movss,movups,endbr64
/usr/bin/ls,295,798,110,22,31,247,544,825,1475,1,4,39,60,49,729,9,10,17,38,25,2,1170,1002,573,15,3,41,84,1062,721,133,101,53,21,3,1,3,37,49,9,4,3,18,25,12,6,350,0,11,6,2,4,2,4,1,0,5,12,38,30,1,4,6,5,1,0,3,0,1,6,5,1,14,0,6,8,3,1,2,2,3,1,1,11,4,10,6,29,16,898,6141,36,4,0,0,19,87,409,1083,753,1,17,1,12,13,6
/usr/bin/bash,706,3779,1110,127,141,1398,2210,5364,7602,1,0,240,316,99,9272,23,31,7,68,3,12,12679,6805,3774,0,1,52,86,9428,5864,321,326,300,120,0,85,130,590,336,0,0,0,0,3,0,0,1921,1,1,0,0,0,0,0,1,14,2,8,170,161,4,3,10,13,6,11,13,10,0,0,44,5,6,1,0,0,0,0,0,0,0,0,9,137,0,0,0,214,0,6387,45623,103,31,1,4,237,1601,1557,7635,5332,20,0,0,0,44,5

Progress and errors are written to stderr. The CSV lines are written to stdout.

Why?

There exist about 1500+ instructions in x86-64. If one wanted to learn x86-64, maybe it is reasonable to look into which instructions are the most used.

Which lead me to the question, which instruction is the most popular? How about the top 5? What if I could count them all?

Why does x86 have so many variations in jump instructions?

Building

Download the source.

git clone https://github.com/sir-ragna/popularity-contest.git

This project depends on nmd. Update the git submodule to download it.

git submodule update --init --recursive

Then you can compile it with your compiler of choice.

gcc -Wall -O2 -o main main.c

There is also a Makefile. It has make release, make debug and make perf. Check perf.md for that last one.

Valgrind

I use valgrind to check for memory leaks. Before you do this I suggest compiling with debug symbols, use -g.

gcc -g -o main main.c
valgrind --leak-check=full --show-leak-kinds=all --track-origins=yes --log-file=valgrind-out.txt ./main /bin/a* 2>/dev/null >/dev/null