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Potential fix for the stackrestore problem #43
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jump.ll: * declare all @llvm.* routines with the correct attributes * use the correct parameter types in @jump_* functions * add `returns_twice` to setjmp/jump_save calls lib.rs: correct handling of `MaybeUninit` * don't immediately call `assume_init()` * use `as_mut_ptr()` as pointer to uninitialized `MaybeUninit` * use `read_volatile()`/`write_volatile()` to let compiler re-read after `jump_swap()`
By coincindence llvm.stackrestore works on x86. The other architectures suffer from the compiler not knowing to use the old stackpointer to load the parameters for %func() and even the value for %func. The correct handling would be to load those values in registers before calling llvm.stackrestore and use the to call %func. This workaround uses alloca to store and load them, which on some architectures (tested on armv7l) works.
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This doesn't actually increase the number of tests that pass. |
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Although it does not fix any tests, it passes on a native armv7l machine with this patch. Also all test cases now fail with sigsegv instead of sigill. Might need an additional fix. |
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Potential fix for the stackrestore problem
By coincindence llvm.stackrestore works on x86. The other architectures
suffer from the compiler not knowing to use the old stackpointer to
load the parameters for %func() and even the value for %func.
The correct handling would be to load those values in registers before
calling llvm.stackrestore and use the to call %func.
This workaround uses alloca to store and load them, which on some
architectures (tested on armv7l) works.
This pull request assumes a merged PR #41