| Issue |
124269
|
| Summary |
lldb - Registers are not restored if PrepareTrivialCall fails
|
| Labels |
lldb
|
| Assignees |
|
| Reporter |
DavidSpickett
|
In this example I have bodged the function to return false after writing the argument registers:
```
(lldb) run
Process 3666152 launched: '/tmp/test.o' (aarch64)
Process 3666152 stopped
* thread #1, name = 'test.o', stop reason = breakpoint 1.1
frame #0: 0x0000aaaaaaaaa72c test.o`main at test.c:4:10
1 int bar(int a) { return a*2; }
2
3 int main() {
-> 4 return 0;
5 }
(lldb) register read --all
General Purpose Registers:
x0 = 0x0000000000000001
x1 = 0x0000fffffffff3a8
x2 = 0x0000fffffffff3b8
x3 = 0x0000aaaaaaaaa72c test.o`main at test.c:4:10
x4 = 0x0000000000000000
x5 = 0x209f561e2fa866d7
x6 = 0x0000fffff7facc90 libc.so.6`initial
x7 = 0x0000004554415649
(lldb) p bar(1)
error: Can't evaluate the _expression_ without a running target due to: Interpreter doesn't handle one of the _expression_'s opcodes
```
Here we should have restored the original values, but:
```
(lldb) register read --all
General Purpose Registers:
x0 = 0x0000000000000063
x1 = 0x0000000000000063
x2 = 0x0000000000000063
x3 = 0x0000000000000063
x4 = 0x0000000000000063
x5 = 0x0000000000000063
```
We did not.
This is 99.9% of the time not a problem as preparing a trivial call does trivial things, but in adding Arm GCS support I had to handle the failure path and found this.
For that, I'm going to handle the one case I need, but I will come back an try to make LLDB restore everything properly.
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