Rather than relying on the stack being 0'ed out always, do it manually.
The stack generally happened to be zero, and because the compiler
realizes that the tests are dealing with chars truncates the read value.
However, the top 3 nibbles of the value are undefined and may be
non-zero. The indirection level caused a null-pointer dereference.
Explicitly scribbling on the stack during the allocation causes test
failures without the original zexting behaviour.
The closure function (invoked as closure->fun in ffi_closure_XXX_inner)
will only populate the actual number of bytes for the true return type,
which may be a character. This leaves garbage on the stack when the
assembly closure function (i.e. ffi_closure_XXX) reads the return value
off of the stack into r0 as a 4-byte value. ffi_closure_XXX always
leaves room for at least 4 bytes here, so we can safely set them to 0.
Otherwise, if there is garbage in any of these bytes, these end up in r0
and in the returned value as well.
Do not modify the ffi_type. Rearrange the tests so that we
quickly eliminate structures that cannot match. Return an
encoded value of element count and base type.
To avoid assigning registers the would fit, once arguments have been on
the stack, we mark all registers as used once we do not find a free
register for the first time.
This provides working closure support on iOS/ARM devices where
PROT_WRITE|PROT_EXEC is not permitted. The code passes basic
smoke tests, but requires further review.
This implements support for re-mapping a shared table of executable
trampolines directly in front of a writable configuration page, working
around PROT_WRITE restrictions for sandboxed applications on Apple's
iOS.
This implementation is for testing purposes; a proper allocator is still
necessary, and ARM-specific code needs to be moved out of
src/closures.c.
Saleem Abdulrasool
Anthony Green
Gregory Pakosz
Johannes Goslar
s1341
Russell Keith-Magee
Richard Henderson
Matthias Klose
Zachary Waldowski
Zachary Waldowski
David Schneider
Anthony Green
Landon Fuller