Add option to pass thread ID to thread select command (#73596)
We'd like a way to select the current thread by its thread ID (rather
than its internal LLDB thread index).
This PR adds a `-t` option (`--thread_id` long option) that tells the
`thread select` command to interpret the `<thread-index>` argument as a
thread ID.
Here's an example of it working:
```
michristensen@devbig356 llvm/llvm-project (thread-select-tid) » ../Debug/bin/lldb ~/scratch/cpp/threading/a.out
(lldb) target create "/home/michristensen/scratch/cpp/threading/a.out"
Current executable set to '/home/michristensen/scratch/cpp/threading/a.out' (x86_64).
(lldb) b 18
Breakpoint 1: where = a.out`main + 80 at main.cpp:18:12, address = 0x0000000000000850
(lldb) run
Process 215715 launched: '/home/michristensen/scratch/cpp/threading/a.out' (x86_64)
This is a thread, i=1
This is a thread, i=2
This is a thread, i=3
This is a thread, i=4
This is a thread, i=5
Process 215715 stopped
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x0000555555400850 a.out`main at main.cpp:18:12
15 for (int i = 0; i < 5; i++) {
16 pthread_create(&thread_ids[i], NULL, foo, NULL);
17 }
-> 18 for (int i = 0; i < 5; i++) {
19 pthread_join(thread_ids[i], NULL);
20 }
21 return 0;
(lldb) thread select 2
* thread #2, name = 'a.out'
frame #0: 0x00007ffff68f9918 libc.so.6`__nanosleep + 72
libc.so.6`__nanosleep:
-> 0x7ffff68f9918 <+72>: cmpq $-0x1000, %rax ; imm = 0xF000
0x7ffff68f991e <+78>: ja 0x7ffff68f9952 ; <+130>
0x7ffff68f9920 <+80>: movl %edx, %edi
0x7ffff68f9922 <+82>: movl %eax, 0xc(%rsp)
(lldb) thread info
thread #2: tid = 216047, 0x00007ffff68f9918 libc.so.6`__nanosleep + 72, name = 'a.out'
(lldb) thread list
Process 215715 stopped
thread #1: tid = 215715, 0x0000555555400850 a.out`main at main.cpp:18:12, name = 'a.out', stop reason = breakpoint 1.1
* thread #2: tid = 216047, 0x00007ffff68f9918 libc.so.6`__nanosleep + 72, name = 'a.out'
thread #3: tid = 216048, 0x00007ffff68f9918 libc.so.6`__nanosleep + 72, name = 'a.out'
thread #4: tid = 216049, 0x00007ffff68f9918 libc.so.6`__nanosleep + 72, name = 'a.out'
thread #5: tid = 216050, 0x00007ffff68f9918 libc.so.6`__nanosleep + 72, name = 'a.out'
thread #6: tid = 216051, 0x00007ffff68f9918 libc.so.6`__nanosleep + 72, name = 'a.out'
(lldb) thread select 215715
error: invalid thread #215715.
(lldb) thread select -t 215715
* thread #1, name = 'a.out', stop reason = breakpoint 1.1
frame #0: 0x0000555555400850 a.out`main at main.cpp:18:12
15 for (int i = 0; i < 5; i++) {
16 pthread_create(&thread_ids[i], NULL, foo, NULL);
17 }
-> 18 for (int i = 0; i < 5; i++) {
19 pthread_join(thread_ids[i], NULL);
20 }
21 return 0;
(lldb) thread select -t 216051
* thread #6, name = 'a.out'
frame #0: 0x00007ffff68f9918 libc.so.6`__nanosleep + 72
libc.so.6`__nanosleep:
-> 0x7ffff68f9918 <+72>: cmpq $-0x1000, %rax ; imm = 0xF000
0x7ffff68f991e <+78>: ja 0x7ffff68f9952 ; <+130>
0x7ffff68f9920 <+80>: movl %edx, %edi
0x7ffff68f9922 <+82>: movl %eax, 0xc(%rsp)
(lldb) thread select 3
* thread #3, name = 'a.out'
frame #0: 0x00007ffff68f9918 libc.so.6`__nanosleep + 72
libc.so.6`__nanosleep:
-> 0x7ffff68f9918 <+72>: cmpq $-0x1000, %rax ; imm = 0xF000
0x7ffff68f991e <+78>: ja 0x7ffff68f9952 ; <+130>
0x7ffff68f9920 <+80>: movl %edx, %edi
0x7ffff68f9922 <+82>: movl %eax, 0xc(%rsp)
(lldb) thread select -t 216048
* thread #3, name = 'a.out'
frame #0: 0x00007ffff68f9918 libc.so.6`__nanosleep + 72
libc.so.6`__nanosleep:
-> 0x7ffff68f9918 <+72>: cmpq $-0x1000, %rax ; imm = 0xF000
0x7ffff68f991e <+78>: ja 0x7ffff68f9952 ; <+130>
0x7ffff68f9920 <+80>: movl %edx, %edi
0x7ffff68f9922 <+82>: movl %eax, 0xc(%rsp)
(lldb) thread select --thread_id 216048
* thread #3, name = 'a.out'
frame #0: 0x00007ffff68f9918 libc.so.6`__nanosleep + 72
libc.so.6`__nanosleep:
-> 0x7ffff68f9918 <+72>: cmpq $-0x1000, %rax ; imm = 0xF000
0x7ffff68f991e <+78>: ja 0x7ffff68f9952 ; <+130>
0x7ffff68f9920 <+80>: movl %edx, %edi
0x7ffff68f9922 <+82>: movl %eax, 0xc(%rsp)
(lldb) help thread select
Change the currently selected thread.
Syntax: thread select <cmd-options> <thread-index>
Command Options Usage:
thread select [-t] <thread-index>
-t ( --thread_id )
Provide a thread ID instead of a thread index.
This command takes options and free-form arguments. If your arguments
resemble option specifiers (i.e., they start with a - or --), you must use
' -- ' between the end of the command options and the beginning of the
arguments.
(lldb) c
Process 215715 resuming
Process 215715 exited with status = 0 (0x00000000)
```
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