labath added a comment.
This seems suspicious to me, on a couple of levels. You claim that BOOL is an
unsigned type, but the apple documentation
<https://developer.apple.com/documentation/objectivec/bool> says "BOOL is
explicitly signed so @encode(BOOL) is c rather than C even if -funsigned-char
is used." Which one is true? Could this have something to do with the fact
that the documentation assumes obj-c (which does not have a native `bool` type)
but in lldb, we use obj-c++ (which, I guess, inherits `bool` from c++)
everywhere?
If BOOL is unsigned, then it's not clear to me why would
Scalar::ExtractBitfield be sign-extending anything. OTOH, if it is _signed_,
then sign-extension seems to be the right behavior.
I think we may have some deeper problems with the handling bitfields whose
underlying types are 1 byte long. Lldb (I think, correctly) sign-extends all
signed bitfields, except the signed char one:
(lldb) p a
(A) $0 = {
bool_ = true
signed_char = '\x01'
signed_short = -1
signed_int = -1
unsigned_char = '\x01'
unsigned_short = 1
unsigned_int = 1
}
(lldb) p/x a
(A) $1 = {
bool_ = 0x01
signed_char = 0x01
signed_short = 0x0001
signed_int = 0x00000001
unsigned_char = 0x01
unsigned_short = 0x0001
unsigned_int = 0x00000001
}
This patch does not have any impact on this behavior, but the fact that signed
char comes out as '\x01' seems suspicious. This is what gdb does for the same
input:
(gdb) p a
$1 = {bool_ = true, signed_char = -1 '\377', signed_short = -1, signed_int =
-1, unsigned_char = 1 '\001', unsigned_short = 1, unsigned_int = 1}
(gdb) p/x a
$2 = {bool_ = 0x1, signed_char = 0xff, signed_short = 0xffff, signed_int =
0xffffffff, unsigned_char = 0x1, unsigned_short = 0x1, unsigned_int = 0x1}
Finally, even though I'm not sure this is the right solution, I am sure that
`GetValueAsSigned` should get the same fix as `GetValueAsUnsigned`
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D93421/new/
https://reviews.llvm.org/D93421
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