The unpac monorepo manager self-hosting as a monorepo using unpac
runtime/mlvalues.h: more careful definition of Tag_val (#12703)
The offset `- sizeof(value)` should be signed, otherwise pointer overflow
can (formally) occur.
Fixes: #12528
authored by
Xavier Leroy
and committed by
GitHub
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Changes
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Changes
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(Miod Vallat and Xavier Leroy, report by Jan Midtgaard, review by
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KC Sivaramakrishnan)
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- #12528, #12703: Avoid pointer arithmetic overflow in Tag_val macro
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(very likely harmless, but can trigger alarms)
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(Xavier Leroy, report by Sam Goldman, review by Guillaume Munch-Maccagnoni)
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- #12593: TSan should handle Effect.Unhandled correctly
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(Fabrice Buoro and Olivier Nicole, report by Jan Midtgaard and Miod Vallat,
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review by Gabriel Scherer)
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runtime/caml/mlvalues.h
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runtime/caml/mlvalues.h
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#define Tag_hp(hp) (((volatile unsigned char *) (hp)) [sizeof(value)-1])
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/* Also an l-value. */
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#else
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-
#define Tag_val(val) (((volatile unsigned char *) (val)) [-sizeof(value)])
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#define Tag_val(val) (((volatile unsigned char *) (val)) [- (int)sizeof(value)])
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/* Also an l-value. */
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#define Tag_hp(hp) (((volatile unsigned char *) (hp)) [0])
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/* Also an l-value. */