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Martin Storsjö 65739691b9 checkasm: Generalize crash handling This replaces the riscv specific handling from `7212466e73` (which essentially is reverted), with a different implementation of the same (plus a bit more), based on the corresponding feature in dav1d's checkasm, supporting both Unix and Windows. See in particular the dav1d commits 0b6ee30eab2400e4f85b735ad29a68a842c34e21, 0421f787ea592fd2cc74c887f20b8dc31393788b, 8501a4b20135f93a4c3b426468e2240e872949c5 and d23e87f7aee26ddcf5f7a2e185112031477599a7, authored by Henrik Gramner. The overall approach compared to the existing implementation for riscv is the same; set up a signal handler, store the state with sigsetjmp, jump out of the crashing function with siglongjmp. The main difference is in what happens when the signal handler is invoked. In the previous implementation, it would resume from right before calling the crashing function, and then skip that call based on the setjmp return value. In the imported implementation from dav1d, we return to right before the check_func() call, which will skip testing the current function (as the pointer is the same as it was before). Other differences are: - Support for other signal handling mechanisms (Windows AddVectoredExceptionHandler) - Using RtlCaptureContext/RtlRestoreContext instead of setjmp/longjmp on Windows with SEH - Only catching signals once per function - if more than one signal is delivered before signal handling is reenabled, any signal is handled as it would without our handler - Not using an arch specific signal handler written in assembly Signed-off-by: Martin Storsjö <martin@martin.st>	12 months ago
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checkasm.S	checkasm: Generalize crash handling	12 months ago

Martin Storsjö 65739691b9 checkasm: Generalize crash handling

This replaces the riscv specific handling from
7212466e73 (which essentially is
reverted), with a different implementation of the same (plus a bit
more), based on the corresponding feature in dav1d's checkasm,
supporting both Unix and Windows.

See in particular the dav1d commits
0b6ee30eab2400e4f85b735ad29a68a842c34e21,
0421f787ea592fd2cc74c887f20b8dc31393788b,
8501a4b20135f93a4c3b426468e2240e872949c5 and
d23e87f7aee26ddcf5f7a2e185112031477599a7, authored by Henrik Gramner.

The overall approach compared to the existing implementation for
riscv is the same; set up a signal handler, store the state with
sigsetjmp, jump out of the crashing function with siglongjmp.

The main difference is in what happens when the signal handler
is invoked. In the previous implementation, it would resume from
right before calling the crashing function, and then skip that call
based on the setjmp return value.

In the imported implementation from dav1d, we return to right before
the check_func() call, which will skip testing the current function
(as the pointer is the same as it was before).

Other differences are:
- Support for other signal handling mechanisms (Windows
  AddVectoredExceptionHandler)
- Using RtlCaptureContext/RtlRestoreContext instead of setjmp/longjmp
  on Windows with SEH
- Only catching signals once per function - if more than one
  signal is delivered before signal handling is reenabled, any
  signal is handled as it would without our handler
- Not using an arch specific signal handler written in assembly

Signed-off-by: Martin Storsjö <martin@martin.st>

12 months ago

checkasm.S checkasm: Generalize crash handling 12 months ago