7.6
in .symtab? | type | module | section | |
---|---|---|---|---|
buf | Yes | external | m | .data |
bufp0 | Yes | global | swap | .data |
bufp1 | Yes | local | swap | .bss |
swap | Yes | global | swap | .text |
temp | No | ------ | ----- | ------ |
incr | Yes | local | swap | .text |
count | Yes | local | swap | .bss |
7.7
删除行 x = -0.0;
或者
int x 改成 double x
7.8
A.
main.1
main.2
B.
unknown
unknown
C.
error
error
7.9
0xe5894855 is 函数main的前2个指令内容。
7.10
A.
gcc p.o libx.a
B.
gcc p.o libx.a liby.a libx.a
C.
gcc p.o libx.a liby.a libx.a libz.a
7.11
.bss 的空间
7.12
A.
ADDR(s) = ADDR(.text) = 0x4004e0
ADDR(r.symbol) = ADDR(swap) = 0x4004f8
refaddr = ADDR(s) + r.offset = 0x4004ea
*refptr = (unsigned) (ADDR(r.symbol) + r.addend - refaddr) = 0xa
B.
ADDR(s) = ADDR(.text) = 0x4004d0
ADDR(r.symbol) = ADDR(swap) = 0x400500
refaddr = ADDR(s) + r.offset = 0x4004da
*refptr = (unsigned) (ADDR(r.symbol) + r.addend - refaddr) = 0x22
7.13
7.13
A.
libm.a path
whereis libm.a
output:
libm: /usr/lib64/libm.a /usr/lib64/libm.so
libm.a files
ar t /usr/lib64/libm.a
output:
s_lib_version.o
s_matherr.o
s_signgam.o
fclrexcpt.o
fgetexcptflg.o
fraiseexcpt.o
fsetexcptflg.o
ftestexcept.o
fegetround.o
fesetround.o
fegetenv.o
feholdexcpt.o
fesetenv.o
feupdateenv.o
t_exp.o
fedisblxcpt.o
feenablxcpt.o
fegetexcept.o
powl_helper.o
e_acos.o
e_acosh.o
e_asin.o
e_atan2.o
e_atanh.o
....
similar way for libc.a
B.
compile code with -Og and -Og -g
不一样
C.
ldd /usr/bin/gcc
linux-vdso.so.1 => (0x00007ffe99d2f000)
libm.so.6 => /lib64/libm.so.6 (0x00007fc91fb6a000)
libc.so.6 => /lib64/libc.so.6 (0x00007fc91f7a7000)
/lib64/ld-linux-x86-64.so.2 (0x00005646f33c1000)
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