C코드를 ll로 변환 후 Assembly ❤️바꾸는 방법(LLVM&Assembly코드는 M1pro arm64기계 기준임macOS)otool활용

한글강의Assembly언어001_ld_as_C언어_Assembly언어로 변환 #assembly
https://youtu.be/9yt1Enp4EwU

Arm64 Assembly Cheat Sheet
잘 정리됨
https://modexp.wordpress.com/2018/10/30/arm64-assembly/

A Guide to ARM64 / AArch64 Assembly on Linux with Shellcodes and Cryptography

Rust❤️
Rust❤️러스트 .o 오브젝트(obj❤️) 파일 만드는 방법How create .obj file from Rust code -
https://economiceco.tistory.com/m/14900

Rust❤️러스트 .o 오브젝트(obj❤️) 파일 만드는 방법How create .obj file from Rust code

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내가 공부하려고 정리한 Github

https://github.com/YoungHaKim7/Arm64_Assembly_Language

GitHub - YoungHaKim7/Arm64_Assembly_Language

LLVM -IR 대해
https://ji007.tistory.com/4

LLVM (Low Level Virtual Machine)

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9분6초에 나옴

5. C to Assembly

자료 출처 MIT
https://youtu.be/wt7a5BOztuM

테스트 C코드

fib.c

#include <stdio.h>
#include <stdlib.h>

int fib(int n) {
    int i, j;
    if (n < 2)
        return n;
    i = fib(n - 1);
    j = fib(n - 2);
    return (i + j);
}

int main() {
    int n = 40;
    printf("fib(%d) %d \n", n, fib(n));

    return 0;

}

clang 으로 LLVM IR Code 로 우선 변환

clang -S -emit-llvm fib.c

fib.c 가 fib.ll 변환됨

fib.ll

; ModuleID = 'fib.c'
source_filename = "fib.c"
target datalayout = "e-m:o-i64:64-i128:128-n32:64-S128"
target triple = "arm64-apple-macosx12.0.0"

@.str = private unnamed_addr constant [13 x i8] c"fib(%d) %d \0A\00", align 1

; Function Attrs: noinline nounwind optnone ssp uwtable
define i32 @fib(i32 %0) #0 {
  %2 = alloca i32, align 4
  %3 = alloca i32, align 4
  %4 = alloca i32, align 4
  %5 = alloca i32, align 4
  store i32 %0, i32* %3, align 4
  %6 = load i32, i32* %3, align 4
  %7 = icmp slt i32 %6, 2
  br i1 %7, label %8, label %10

8:                                                ; preds = %1
  %9 = load i32, i32* %3, align 4
  store i32 %9, i32* %2, align 4
  br label %20

10:                                               ; preds = %1
  %11 = load i32, i32* %3, align 4
  %12 = sub nsw i32 %11, 1
  %13 = call i32 @fib(i32 %12)
  store i32 %13, i32* %4, align 4
  %14 = load i32, i32* %3, align 4
  %15 = sub nsw i32 %14, 2
  %16 = call i32 @fib(i32 %15)
  store i32 %16, i32* %5, align 4
  %17 = load i32, i32* %4, align 4
  %18 = load i32, i32* %5, align 4
  %19 = add nsw i32 %17, %18
  store i32 %19, i32* %2, align 4
  br label %20

20:                                               ; preds = %10, %8
  %21 = load i32, i32* %2, align 4
  ret i32 %21
}

; Function Attrs: noinline nounwind optnone ssp uwtable
define i32 @main() #0 {
  %1 = alloca i32, align 4
  %2 = alloca i32, align 4
  store i32 0, i32* %1, align 4
  store i32 40, i32* %2, align 4
  %3 = load i32, i32* %2, align 4
  %4 = load i32, i32* %2, align 4
  %5 = call i32 @fib(i32 %4)
  %6 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @.str, i64 0, i64 0), i32 %3, i32 %5)
  ret i32 0
}

declare i32 @printf(i8*, ...) #1

attributes #0 = { noinline nounwind optnone ssp uwtable "frame-pointer"="non-leaf" "min-legal-vector-width"="0" "no-trapping-math"="true" "probe-stack"="__chkstk_darwin" "stack-protector-buffer-size"="8" "target-cpu"="apple-m1" "target-features"="+aes,+crc,+crypto,+dotprod,+fp-armv8,+fp16fml,+fullfp16,+lse,+neon,+ras,+rcpc,+rdm,+sha2,+sha3,+sm4,+v8.5a,+zcm,+zcz" }
attributes #1 = { "frame-pointer"="non-leaf" "no-trapping-math"="true" "probe-stack"="__chkstk_darwin" "stack-protector-buffer-size"="8" "target-cpu"="apple-m1" "target-features"="+aes,+crc,+crypto,+dotprod,+fp-armv8,+fp16fml,+fullfp16,+lse,+neon,+ras,+rcpc,+rdm,+sha2,+sha3,+sm4,+v8.5a,+zcm,+zcz" }

!llvm.module.flags = !{!0, !1, !2, !3, !4, !5, !6, !7, !8}
!llvm.ident = !{!9}

!0 = !{i32 2, !"SDK Version", [2 x i32] [i32 12, i32 3]}
!1 = !{i32 1, !"wchar_size", i32 4}
!2 = !{i32 1, !"branch-target-enforcement", i32 0}
!3 = !{i32 1, !"sign-return-address", i32 0}
!4 = !{i32 1, !"sign-return-address-all", i32 0}
!5 = !{i32 1, !"sign-return-address-with-bkey", i32 0}
!6 = !{i32 7, !"PIC Level", i32 2}
!7 = !{i32 7, !"uwtable", i32 1}
!8 = !{i32 7, !"frame-pointer", i32 1}
!9 = !{!"Apple clang version 13.1.6 (clang-1316.0.21.2.5)"}

변환 된 fib.ll파일을 fib.s 어셈블리 파일로 다시 변환

clang fib.ll -S

fib.s 코드

	.section	__TEXT,__text,regular,pure_instructions
	.build_version macos, 12, 0	sdk_version 12, 3
	.global	_fib                            ; -- Begin function fib
	.p2align	2
_fib:                                   ; @fib
	.cfi_startproc
; %bb.0:
	sub	sp, sp, #32
	stp	x29, x30, [sp, #16]             ; 16-byte Folded Spill
	add	x29, sp, #16
	.cfi_def_cfa w29, 16
	.cfi_offset w30, -8
	.cfi_offset w29, -16
	str	w0, [sp, #8]
	ldr	w8, [sp, #8]
	subs	w8, w8, #2
	b.ge	LBB0_2
	b	LBB0_1
LBB0_1:
	ldr	w8, [sp, #8]
	stur	w8, [x29, #-4]
	b	LBB0_3
LBB0_2:
	ldr	w8, [sp, #8]
	subs	w0, w8, #1
	bl	_fib
	str	w0, [sp, #4]
	ldr	w8, [sp, #8]
	subs	w0, w8, #2
	bl	_fib
	str	w0, [sp]
	ldr	w8, [sp, #4]
	ldr	w9, [sp]
	add	w8, w8, w9
	stur	w8, [x29, #-4]
	b	LBB0_3
LBB0_3:
	ldur	w0, [x29, #-4]
	ldp	x29, x30, [sp, #16]             ; 16-byte Folded Reload
	add	sp, sp, #32
	ret
	.cfi_endproc
                                        ; -- End function
	.global	_main                           ; -- Begin function main
	.p2align	2
_main:                                  ; @main
	.cfi_startproc
; %bb.0:
	sub	sp, sp, #64
	stp	x29, x30, [sp, #48]             ; 16-byte Folded Spill
	add	x29, sp, #48
	.cfi_def_cfa w29, 16
	.cfi_offset w30, -8
	.cfi_offset w29, -16
	mov	w8, #0
	stur	w8, [x29, #-12]                 ; 4-byte Folded Spill
	stur	wzr, [x29, #-4]
	mov	w8, #40
	stur	w8, [x29, #-8]
	ldur	w9, [x29, #-8]
                                        ; implicit-def: $x8
	mov	x8, x9
	str	x8, [sp, #24]                   ; 8-byte Folded Spill
	ldur	w0, [x29, #-8]
	bl	_fib
	ldr	x8, [sp, #24]                   ; 8-byte Folded Reload
	mov	x10, x0
	adrp	x0, l_.str@PAGE
	add	x0, x0, l_.str@PAGEOFF
	mov	x9, sp
	str	x8, [x9]
                                        ; implicit-def: $x8
	mov	x8, x10
	str	x8, [x9, #8]
	bl	_printf
	ldur	w0, [x29, #-12]                 ; 4-byte Folded Reload
	ldp	x29, x30, [sp, #48]             ; 16-byte Folded Reload
	add	sp, sp, #64
	ret
	.cfi_endproc
                                        ; -- End function
	.section	__TEXT,__cstring,cstring_literals
l_.str:                                 ; @.str
	.asciz	"fib(%d) %d \n"

.subsections_via_symbols

// 링크로 연결해서 실행 파일 만들기

ld -macosx_version_min 12.0.0 -o fib fib.o -lSystem -syslibroot `xcrun -sdk macosx --show-sdk-path` -e _main -arch arm64



ls
fib    fib.c  fib.ll fib.o  fib.s




./fib
fib(40) 102334155

gcc -o fib -Wall fib.c


ls

fib    fib.c  fib.ll fib.o  fib.s





// otool 을 이용해 Assembly 코드를 볼 수 있다.
otool -tv fib

fib:
(__TEXT,__text) section
_fib:
0000000100003ec4	sub	sp, sp, #0x20
0000000100003ec8	stp	x29, x30, [sp, #0x10]
0000000100003ecc	add	x29, sp, #0x10
0000000100003ed0	str	w0, [sp, #0x8]
0000000100003ed4	ldr	w8, [sp, #0x8]
0000000100003ed8	subs	w8, w8, #0x2
0000000100003edc	b.ge	0x100003ef0
0000000100003ee0	b	0x100003ee4
0000000100003ee4	ldr	w8, [sp, #0x8]
0000000100003ee8	stur	w8, [x29, #-0x4]
0000000100003eec	b	0x100003f24
0000000100003ef0	ldr	w8, [sp, #0x8]
0000000100003ef4	subs	w0, w8, #0x1
0000000100003ef8	bl	_fib
0000000100003efc	str	w0, [sp, #0x4]
0000000100003f00	ldr	w8, [sp, #0x8]
0000000100003f04	subs	w0, w8, #0x2
0000000100003f08	bl	_fib
0000000100003f0c	str	w0, [sp]
0000000100003f10	ldr	w8, [sp, #0x4]
0000000100003f14	ldr	w9, [sp]
0000000100003f18	add	w8, w8, w9
0000000100003f1c	stur	w8, [x29, #-0x4]
0000000100003f20	b	0x100003f24
0000000100003f24	ldur	w0, [x29, #-0x4]
0000000100003f28	ldp	x29, x30, [sp, #0x10]
0000000100003f2c	add	sp, sp, #0x20
0000000100003f30	ret
_main:
0000000100003f34	sub	sp, sp, #0x40
0000000100003f38	stp	x29, x30, [sp, #0x30]
0000000100003f3c	add	x29, sp, #0x30
0000000100003f40	mov	w8, #0x0
0000000100003f44	stur	w8, [x29, #-0xc]
0000000100003f48	stur	wzr, [x29, #-0x4]
0000000100003f4c	mov	w8, #0x28
0000000100003f50	stur	w8, [x29, #-0x8]
0000000100003f54	ldur	w9, [x29, #-0x8]
0000000100003f58	mov	x8, x9
0000000100003f5c	str	x8, [sp, #0x18]
0000000100003f60	ldur	w0, [x29, #-0x8]
0000000100003f64	bl	_fib
0000000100003f68	ldr	x8, [sp, #0x18]
0000000100003f6c	mov	x10, x0
0000000100003f70	adrp	x0, 0 ; 0x100003000
0000000100003f74	add	x0, x0, #0xfa8 ; literal pool for: "fib(%d) %d \n"
0000000100003f78	mov	x9, sp
0000000100003f7c	str	x8, [x9]
0000000100003f80	mov	x8, x10
0000000100003f84	str	x8, [x9, #0x8]
0000000100003f88	bl	0x100003f9c ; symbol stub for: _printf
0000000100003f8c	ldur	w0, [x29, #-0xc]
0000000100003f90	ldp	x29, x30, [sp, #0x30]
0000000100003f94	add	sp, sp, #0x40
0000000100003f98	ret

arm64 Assembly 해석하는 방법

https://github.com/Siguza/ios-resources/blob/master/bits/arm64.md

GitHub - Siguza/ios-resources: Useful resources for iOS hacking

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otool 활용법(macOS)

Comparing C to machine language

https://www.youtube.com/watch?v=yOyaJXpAYZQ

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C언어 int_64 해결 힌트
https://stackoverflow.com/questions/31534474/format-lld-expects-type-long-long-int-but-argument-4-has-type-int64-t

format '%lld' expects type 'long long int', but argument 4 has type 'int64_t'

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