Differential D28233 Diff 82729 contrib/elftoolchain/libdwarf/libdwarf_rw.c

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contrib/elftoolchain/libdwarf/libdwarf_rw.c

Show First 20 Lines • Show All 278 Lines • ▼ Show 20 Lines	_dwarf_read_sleb128(uint8_t data, uint64_t offsetp)
uint8_t b;		uint8_t b;
int shift = 0;		int shift = 0;
uint8_t *src;		uint8_t *src;

src = data + *offsetp;		src = data + *offsetp;

do {		do {
b = *src++;		b = *src++;
ret \|= ((b & 0x7f) << shift);		ret \|= ((uint64_t)(b & 0x7f) << shift);
		jrtc27Unsubmitted Not Done Inline Actions Is setting the MSB with `\|` less UB than shifting into it? jrtc27: Is setting the MSB with `\|` less UB than shifting into it?
		arichardsonAuthorUnsubmitted Done Inline Actions I didn't get an error, but it's possible that it would be one. Maybe it just wasn't triggered with the given inputs. arichardson: I didn't get an error, but it's possible that it would be one. Maybe it just wasn't triggered…
(*offsetp)++;		(*offsetp)++;
shift += 7;		shift += 7;
} while ((b & 0x80) != 0);		} while ((b & 0x80) != 0);

if (shift < 64 && (b & 0x40) != 0)		if (shift < 64 && (b & 0x40) != 0)
ret \|= (-1 << shift);		ret \|= (UINT64_MAX << shift);
		jrtc27Unsubmitted Not Done Inline Actions Does this want to be `(int64_t)-1` or something instead? Using `UINT64_MAX` is a bit weird. jrtc27: Does this want to be `(int64_t)-1` or something instead? Using `UINT64_MAX` is a bit weird.
		arichardsonAuthorUnsubmitted Done Inline Actions (int64_t)-1 still shifts the sign bits. We have to use an unsigned type to silence the warning. arichardson: (int64_t)-1 still shifts the sign bits. We have to use an unsigned type to silence the warning.
		jrtc27Unsubmitted Not Done Inline Actions Ah, right, the UB is specifically anything that's not left-shifting a non-negative value to give a still-representable result. jrtc27: Ah, right, the UB is specifically anything that's not left-shifting a non-negative value to…

return (ret);		return (ret);
}		}

int		int
_dwarf_write_sleb128(uint8_t data, uint8_t end, int64_t val)		_dwarf_write_sleb128(uint8_t data, uint8_t end, int64_t val)
{		{
uint8_t *p;		uint8_t *p;
▲ Show 20 Lines • Show All 46 Lines • ▼ Show 20 Lines	_dwarf_read_uleb128(uint8_t data, uint64_t offsetp)
uint8_t b;		uint8_t b;
int shift = 0;		int shift = 0;
uint8_t *src;		uint8_t *src;

src = data + *offsetp;		src = data + *offsetp;

do {		do {
b = *src++;		b = *src++;
ret \|= ((b & 0x7f) << shift);		ret \|= ((uint64_t)(b & 0x7f) << shift);
(*offsetp)++;		(*offsetp)++;
shift += 7;		shift += 7;
} while ((b & 0x80) != 0);		} while ((b & 0x80) != 0);

return (ret);		return (ret);
}		}

int		int
▲ Show 20 Lines • Show All 45 Lines • ▼ Show 20 Lines	_dwarf_decode_sleb128(uint8_t **dp)
int64_t ret = 0;		int64_t ret = 0;
uint8_t b;		uint8_t b;
int shift = 0;		int shift = 0;

uint8_t src = dp;		uint8_t src = dp;

do {		do {
b = *src++;		b = *src++;
ret \|= ((b & 0x7f) << shift);		ret \|= ((uint64_t)(b & 0x7f) << shift);
shift += 7;		shift += 7;
} while ((b & 0x80) != 0);		} while ((b & 0x80) != 0);

if (shift < 64 && (b & 0x40) != 0)		if (shift < 64 && (b & 0x40) != 0)
ret \|= (-1 << shift);		ret \|= (UINT64_MAX << shift);
		markjUnsubmitted Done Inline Actions Same problem here, no? markj: Same problem here, no?
		arichardsonAuthorUnsubmitted Done Inline Actions Yes, I guess that path just didn't get executed during buildworld. Will update patch. arichardson: Yes, I guess that path just didn't get executed during buildworld. Will update patch.

*dp = src;		*dp = src;

return (ret);		return (ret);
}		}

uint64_t		uint64_t
_dwarf_decode_uleb128(uint8_t **dp)		_dwarf_decode_uleb128(uint8_t **dp)
{		{
uint64_t ret = 0;		uint64_t ret = 0;
uint8_t b;		uint8_t b;
int shift = 0;		int shift = 0;

uint8_t src = dp;		uint8_t src = dp;

do {		do {
b = *src++;		b = *src++;
ret \|= ((b & 0x7f) << shift);		ret \|= ((uint64_t)(b & 0x7f) << shift);
		arichardsonAuthorUnsubmitted Done Inline Actions And here. arichardson: And here.
shift += 7;		shift += 7;
} while ((b & 0x80) != 0);		} while ((b & 0x80) != 0);

*dp = src;		*dp = src;

return (ret);		return (ret);
}		}

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