Hi Marek, On 3/8/25 9:12 PM, Marek Vasut wrote:
Fix the following conversion overflow errors. The input field is already limited to 3/2/1 bits using the bitwise and, move the parenthesis around to avoid the bogus warning:" fs/exfat/utf.c: In function ‘utf8_to_wchar’: fs/exfat/utf.c:165:23: warning: overflow in conversion from ‘int’ to ‘wchar_t’ {aka ‘short unsigned int’} changes value from ‘(int)(short unsigned int)*input << 18 & 1835008’ to ‘0’ [-Woverflow] 165 | *wc = ((wchar_t) input[0] & 0x07) << 18; | ^ fs/exfat/utf.c:170:23: warning: overflow in conversion from ‘int’ to ‘wchar_t’ {aka ‘short unsigned int’} changes value from ‘(int)(short unsigned int)*input << 24 & 50331648’ to ‘0’ [-Woverflow] 170 | *wc = ((wchar_t) input[0] & 0x03) << 24; | ^ fs/exfat/utf.c:175:23: warning: overflow in conversion from ‘int’ to ‘wchar_t’ {aka ‘short unsigned int’} changes value from ‘(int)(short unsigned int)*input << 30 & 1073741824’ to ‘0’ [-Woverflow] 175 | *wc = ((wchar_t) input[0] & 0x01) << 30; | ^ "
Since this doesn't seem to be U-Boot-specific, any chance to open a Pull Request on the project so we may be able to not carry this patch when upgrading (yes, the last commit in the branch was two years ago, but it seems the maintainer is still active on issues).
Considering that wchar_t is an unsigned short int and that USHRT_MAX is 0xffff (so 2B or 16b)...
Signed-off-by: Marek Vasut <[email protected]> --- Cc: Baruch Siach <[email protected]> Cc: Francesco Dolcini <[email protected]> Cc: Heinrich Schuchardt <[email protected]> Cc: Hiago De Franco <[email protected]> Cc: Ilias Apalodimas <[email protected]> Cc: Nam Cao <[email protected]> Cc: Simon Glass <[email protected]> Cc: Sughosh Ganu <[email protected]> Cc: Tom Rini <[email protected]> Cc: [email protected] --- fs/exfat/utf.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/exfat/utf.c b/fs/exfat/utf.c index b1d09e76478..5be8dcc2170 100644 --- a/fs/exfat/utf.c +++ b/fs/exfat/utf.c @@ -162,17 +162,17 @@ static const char* utf8_to_wchar(const char* input, wchar_t* wc, } else if ((input[0] & 0xf8) == 0xf0) { - *wc = ((wchar_t) input[0] & 0x07) << 18; + *wc = (wchar_t)((input[0] & 0x07) << 18); size = 4; } else if ((input[0] & 0xfc) == 0xf8) { - *wc = ((wchar_t) input[0] & 0x03) << 24; + *wc = (wchar_t)((input[0] & 0x03) << 24); size = 5; } else if ((input[0] & 0xfe) == 0xfc) { - *wc = ((wchar_t) input[0] & 0x01) << 30; + *wc = (wchar_t)((input[0] & 0x01) << 30);
... wouldn't those still overflow? I assume unsigned short int like int may have an architecture-dependent size, but seems to be at least 2B, which wouldn't be enough to store all that?
Cheers, Quentin
