1.15. SWITCH()/CASE/DEFAULT
.byte (.L3 - .Lrtx4) / 4 ; case 10
.byte (.L2 - .Lrtx4) / 4 ; case 11
.byte (.L2 - .Lrtx4) / 4 ; case 12
.byte (.L2 - .Lrtx4) / 4 ; case 13
.byte (.L2 - .Lrtx4) / 4 ; case 14
.byte (.L2 - .Lrtx4) / 4 ; case 15
.byte (.L2 - .Lrtx4) / 4 ; case 16
.byte (.L2 - .Lrtx4) / 4 ; case 17
.byte (.L2 - .Lrtx4) / 4 ; case 18
.byte (.L2 - .Lrtx4) / 4 ; case 19
.byte (.L6 - .Lrtx4) / 4 ; case 20
.byte (.L6 - .Lrtx4) / 4 ; case 21
.byte (.L7 - .Lrtx4) / 4 ; case 22
.text
; everything after ".text" statement is allocated in the code (text) segment:
.L7:
; print "22"
adrp x0, .LC3
add x0, x0, :lo12:.LC3
b puts
.L6:
; print "8, 9, 21"
adrp x0, .LC2
add x0, x0, :lo12:.LC2
b puts
.L5:
; print "3, 4, 5"
adrp x0, .LC1
add x0, x0, :lo12:.LC1
b puts
.L3:
; print "1, 2, 7, 10"
adrp x0, .LC0
add x0, x0, :lo12:.LC0
b puts
.LC0:
.string "1, 2, 7, 10"
.LC1:
.string "3, 4, 5"
.LC2:
.string "8, 9, 21"
.LC3:
.string "22"
.LC4:
.string "default"
Let’s compile this example to object file and open it inIDA. Here is the jump table:
Listing 1.160: jumptable in IDA.rodata:0000000000000064 AREA .rodata, DATA, READONLY
.rodata:0000000000000064 ; ORG 0x64
.rodata:0000000000000064 $d DCB 9 ; case 1
.rodata:0000000000000065 DCB 9 ; case 2
.rodata:0000000000000066 DCB 6 ; case 3
.rodata:0000000000000067 DCB 6 ; case 4
.rodata:0000000000000068 DCB 6 ; case 5
.rodata:0000000000000069 DCB 6 ; case 6
.rodata:000000000000006A DCB 9 ; case 7
.rodata:000000000000006B DCB 3 ; case 8
.rodata:000000000000006C DCB 3 ; case 9
.rodata:000000000000006D DCB 9 ; case 10
.rodata:000000000000006E DCB 0xF7 ; case 11
.rodata:000000000000006F DCB 0xF7 ; case 12
.rodata:0000000000000070 DCB 0xF7 ; case 13
.rodata:0000000000000071 DCB 0xF7 ; case 14
.rodata:0000000000000072 DCB 0xF7 ; case 15
.rodata:0000000000000073 DCB 0xF7 ; case 16
.rodata:0000000000000074 DCB 0xF7 ; case 17
.rodata:0000000000000075 DCB 0xF7 ; case 18
.rodata:0000000000000076 DCB 0xF7 ; case 19