1. 反向調(diào)試

gdb支持程序反向執(zhí)行。

record??讓程序開始記錄反向調(diào)試所必要的信息

rn :?reverse next

rc: reverse continue ，Continue program being debugged but run?it in reverse

record stop:?停止記錄

2.?格式化（pretty print）打印結(jié)構(gòu)體內(nèi)容

GDB調(diào)試C程序時(shí)，默認(rèn)情況下輸出很不直觀，看起來很費(fèi)勁.

set print pretty on

3.AddressSanitizerAndDebugger

https://github.com/google/sanitizers/wiki/AddressSanitizerAndDebugger

b __asan::ReportGenericError

p?__asan_describe_address(0x7ffff73c3f80)

4. 條件斷點(diǎn)不生效

設(shè)置條件斷點(diǎn):

cond 1?$rdi==0x0? ?//在斷點(diǎn)一設(shè)置條件斷點(diǎn)

b 57 if?$rdi==0x0? ?//在當(dāng)前文件的57行設(shè)置條件斷點(diǎn)

有時(shí)候你會(huì)發(fā)現(xiàn)條件斷點(diǎn)沒有生效，我的解決方案是，先單步運(yùn)行(n)幾行，在運(yùn)行c.

Greg 在他的blog中也提到過這個(gè)問題：http://www.brendangregg.com/blog/2016-08-09/gdb-example-ncurses.html

5. Command 阻塞

上例中在斷點(diǎn)1設(shè)置command,? 先打印堆棧，再continue, 你會(huì)發(fā)現(xiàn)gdb 還是會(huì)被自動(dòng)阻塞住。

你需要在gdb的配置文件.gdbinit中添加?set height 0，?會(huì)自動(dòng)避免阻塞問題

6.ptype

Print definition of type TYPE. 可以顯示類型的定義。

有個(gè)重要參數(shù): \o

/o ? ?? ?print offsets and sizes??of fields in a struct (like pahole)

struct tuv
{
int a1;
char *a2;
int a3;
};

(gdb) ptype /o struct tuv
/* offset | size */ type = struct tuv {
/* 0 | 4 */ int a1;
/* XXX 4-byte hole */
/* 8 | 8 */ char *a2;
/* 16 | 4 */ int a3;
/* total size (bytes): 24 */
}

Notice the format of the first column of comments. There, you
can find two parts separated by the ‘|’ character: the offset, which
indicates where the field is located inside the struct, in bytes, and
the size of the field. Another interesting line is the marker of a hole
in the struct, indicating that it may be possible to pack the struct
and make it use less space by reorganizing its fields.

7 File filename

修改code后，重新build。

gdb無須退出，在gdb中運(yùn)行 file a.out?命令，新編譯的a.out會(huì)自動(dòng)加載到gdb。

8.?調(diào)試多線程

info threads

thread 1

set scheduler-locking on/off/step

set?schedule-multiple on/off

thead apply all bt

thead apply 1 bt

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