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| author | Stefan Liebler <stli@linux.ibm.com> | 2019-07-02 14:07:44 +0200 |
|---|---|---|
| committer | Stefan Liebler <stli@linux.ibm.com> | 2019-07-02 14:07:44 +0200 |
| commit | d1bc2cbbed9aea2017ef941f63c8786571da5b4f (patch) | |
| tree | eb77d636ea206639a5ea99ce0f37e223a954e163 | |
| parent | 72edea80c1bb402f41d8bca58c835abf46dadd48 (diff) | |
| download | glibc-d1bc2cbbed9aea2017ef941f63c8786571da5b4f.tar.gz glibc-d1bc2cbbed9aea2017ef941f63c8786571da5b4f.tar.xz glibc-d1bc2cbbed9aea2017ef941f63c8786571da5b4f.zip | |
Fix build warnings in resolv/res_send.c
This patch fixes the gcc warnings seen with gcc 9 -march>=z13 on s390x:
res_send.c: In function ‘__res_context_send’:
res_send.c:498:7: error: ‘resplen’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
498 | if (n == 0 && (buf2 == NULL || *resplen2 == 0))
| ^
In this case send_vc is inlined into __res_context_send
and the maybe uninitialized resplen belongs to the one in send_vc.
In send_vc there is already a DIAG_IGNORE_NEEDS_COMMENT (5, "-Wmaybe-uninitialized")
and a comment which explains that this is a false-positive.
Note that resplen is used as return value.
This patch adds a further DIAG_IGNORE_NEEDS_COMMENT around the declaration of n
in __res_context_send and the comparison after n was set to the return value of send_vc.
ChangeLog:
* resolv/res_send.c (__res_context_send): Disable maybe-uninitialized
warning.
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | resolv/res_send.c | 17 |
2 files changed, 21 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog index 0c7bdd0b0c..3e4d87f15b 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2019-07-02 Stefan Liebler <stli@linux.ibm.com> + + * resolv/res_send.c (__res_context_send): Disable maybe-uninitialized + warning. + 2019-07-01 Florian Weimer <fweimer@redhat.com> * scripts/build-many-glibcs.py (Context.add_all_configs): Add v4t diff --git a/resolv/res_send.c b/resolv/res_send.c index eeeb8acf27..ed27f3abf8 100644 --- a/resolv/res_send.c +++ b/resolv/res_send.c @@ -401,7 +401,18 @@ __res_context_send (struct resolv_context *ctx, int *nansp2, int *resplen2, int *ansp2_malloced) { struct __res_state *statp = ctx->resp; - int gotsomewhere, terrno, try, v_circuit, resplen, n; + int gotsomewhere, terrno, try, v_circuit, resplen; + /* On some architectures send_vc is inlined and the compiler might emit + a warning indicating 'resplen' may be used uninitialized. Note that + the warning belongs to resplen in send_vc which is used as return + value! There the maybe-uninitialized warning is already ignored as + it is a false-positive - see comment in send_vc. + Here the variable n is set to the return value of send_vc. + See below. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (9, "-Wmaybe-uninitialized"); + int n; + DIAG_POP_NEEDS_COMMENT; if (statp->nscount == 0) { __set_errno (ESRCH); @@ -495,8 +506,12 @@ __res_context_send (struct resolv_context *ctx, ansp2_malloced); if (n < 0) return (-1); + /* See comment at the declaration of n. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_NEEDS_COMMENT (9, "-Wmaybe-uninitialized"); if (n == 0 && (buf2 == NULL || *resplen2 == 0)) goto next_ns; + DIAG_POP_NEEDS_COMMENT; } else { /* Use datagrams. */ n = send_dg(statp, buf, buflen, buf2, buflen2, |