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avoid shifting signed integers 31 bits

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We sometimes use 32-bit unsigned integers as bit-fields.
It's fine to access the MSB, because it's unsigned. However,
doing so as "1 << 31" is wrong, because the constant "1" is
a signed int, and we shift into the sign bit, causing
undefined behavior.

We can fix this by using "1U" as the constant.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jeff King 2015-12-29 01:35:46 -05:00 committed by Junio C Hamano
parent 1ff88560c8
commit 9a93c6686f
3 changed files with 3 additions and 3 deletions
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2
builtin/receive-pack.c
View File

@ -1597,7 +1597,7 @@ static void prepare_shallow_update(struct command *commands,
continue;
si->need_reachability_test[i]++;
for (k = 0; k < 32; k++)
if (si->used_shallow[i][j] & (1 << k))
if (si->used_shallow[i][j] & (1U << k))
si->shallow_ref[j * 32 + k]++;
}

2
cache.h
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@ -214,7 +214,7 @@ struct cache_entry {
#define CE_INTENT_TO_ADD (1 << 29)
#define CE_SKIP_WORKTREE (1 << 30)
/* CE_EXTENDED2 is for future extension */
#define CE_EXTENDED2 (1 << 31)
#define CE_EXTENDED2 (1U << 31)
#define CE_EXTENDED_FLAGS (CE_INTENT_TO_ADD | CE_SKIP_WORKTREE)

2
diff.h
View File

@ -91,7 +91,7 @@ typedef struct strbuf *(*diff_prefix_fn_t)(struct diff_options *opt, void *data)
#define DIFF_OPT_DIRSTAT_BY_LINE (1 << 28)
#define DIFF_OPT_FUNCCONTEXT (1 << 29)
#define DIFF_OPT_PICKAXE_IGNORE_CASE (1 << 30)
#define DIFF_OPT_DEFAULT_FOLLOW_RENAMES (1 << 31)
#define DIFF_OPT_DEFAULT_FOLLOW_RENAMES (1U << 31)
#define DIFF_OPT_TST(opts, flag) ((opts)->flags & DIFF_OPT_##flag)
#define DIFF_OPT_TOUCHED(opts, flag) ((opts)->touched_flags & DIFF_OPT_##flag)