0
對象文件的readelf輸出:不正確的函數尺寸
.text段結構我理解Symbol table '.symtab' contains 15 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 00000000 0 NOTYPE LOCAL DEFAULT UND
1: 00000000 0 FILE LOCAL DEFAULT ABS fp16.c
2: 00000000 0 SECTION LOCAL DEFAULT 1
3: 00000000 0 SECTION LOCAL DEFAULT 3
4: 00000000 0 SECTION LOCAL DEFAULT 4
5: 00000000 0 NOTYPE LOCAL DEFAULT 1 $t
6: 00000001 194 FUNC LOCAL DEFAULT 1 __gnu_f2h_internal
7: 00000010 0 NOTYPE LOCAL DEFAULT 5 $d
8: 00000000 0 SECTION LOCAL DEFAULT 5
9: 00000000 0 SECTION LOCAL DEFAULT 7
10: 000000c5 78 FUNC GLOBAL HIDDEN 1 __gnu_h2f_internal
11: 00000115 4 FUNC GLOBAL HIDDEN 1 __gnu_f2h_ieee
12: 00000119 4 FUNC GLOBAL HIDDEN 1 __gnu_h2f_ieee
13: 0000011d 4 FUNC GLOBAL HIDDEN 1 __gnu_f2h_alternative
14: 00000121 4 FUNC GLOBAL HIDDEN 1 __gnu_h2f_alternative
Section Headers:
[Nr] Name Type Addr Off Size ES Flg Lk Inf Al
[ 0] NULL 00000000 000000 000000 00 0 0 0
[ 1] .text PROGBITS 00000000 000034 000124 00 AX 0 0 4
[ 2] .rel.text REL 00000000 00058c 000010 08 9 1 4
[ 3] .data PROGBITS 00000000 000158 000000 00 WA 0 0 1
[ 4] .bss NOBITS 00000000 000158 000000 00 WA 0 0 1
[ 5] .debug_frame PROGBITS 00000000 000158 00008c 00 0 0 4
[ 6] .rel.debug_frame REL 00000000 00059c 000060 08 9 5 4
[ 7] .ARM.attributes ARM_ATTRIBUTES 00000000 0001e4 00002f 00 0 0 1
[ 8] .shstrtab STRTAB 00000000 000213 000051 00 0 0 1
[ 9] .symtab SYMTAB 00000000 00041c 0000f0 10 10 10 4
[10] .strtab STRTAB 00000000 00050c 00007e 00 0 0 1
Relocation section '.rel.text' at offset 0x58c contains 2 entries:
Offset Info Type Sym.Value Sym. Name
0000011a 00000a66 R_ARM_THM_JUMP11 000000c5 __gnu_h2f_internal
00000122 00000a66 R_ARM_THM_JUMP11 000000c5 __gnu_h2f_internal
Relocation section '.rel.debug_frame' at offset 0x59c contains 12 entries:
Offset Info Type Sym.Value Sym. Name
00000014 00000802 R_ARM_ABS32 00000000 .debug_frame
00000018 00000202 R_ARM_ABS32 00000000 .text
00000040 00000802 R_ARM_ABS32 00000000 .debug_frame
00000044 00000202 R_ARM_ABS32 00000000 .text
00000050 00000802 R_ARM_ABS32 00000000 .debug_frame
00000054 00000202 R_ARM_ABS32 00000000 .text
00000060 00000802 R_ARM_ABS32 00000000 .debug_frame
00000064 00000202 R_ARM_ABS32 00000000 .text
00000070 00000802 R_ARM_ABS32 00000000 .debug_frame
00000074 00000202 R_ARM_ABS32 00000000 .text
00000080 00000802 R_ARM_ABS32 00000000 .debug_frame
00000084 00000202 R_ARM_ABS32 00000000 .text
:
.text段具有的量0x124
0x0: unknown byte
0x1-0xC3: __gnu_f2h_internal
0xC3-0xC5: two unknown bytes between those functions (btw what are those?)
0xC5-0x113: __gnu_h2f_internal
0x113-0x115: two unknown bytes between those functions
0x115-0x119: __gnu_f2h_ieee
0x119-0x11D: __gnu_h2f_ieee
0x11D-0x121: __gnu_f2h_alternative
0x121-0x125: __gnu_h2f_alternative // section is only 0x124, what happened to the missing byte?
大小
請注意,段大小爲0x124,最後一個函數在0x125處結束,發生什麼情況會丟失字節?
謝謝。
「區段加載地址」您是指段執行時的虛擬地址?你能舉一個例子來說明如何獲得偏移量?以及如何獲得最後一個函數的正確數據('__gnu_h2f_alternative') – Koten
是的,對不起,在我精確地使用了確切的術語後,我發現「加載地址」可能含糊不清地提示了LMA,當時我確實指的是VMA。在你的例子中,'__gnu_h2f_alternative'看起來是由4個字節(1或2個Thumb指令)組成的,在.text中偏移量爲0x120到0x123,據推測在實際文件中佔用0x154到0x157。 – Notlikethat
感謝您的幫助解釋,爲每個函數獲取正確的原始數據是否正確? 'std :: vector vec; (vec.begin(),section_offset + symbol [i] .st_value&〜1,section_offset + symbol [i] .st_size);' –
Koten