[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448 --- Comment #12 from Aldy Hernandez --- Author: aldyh Date: Wed Sep 13 16:20:27 2017 New Revision: 252253 URL: https://gcc.gnu.org/viewcvs?rev=252253=gcc=rev Log: PR c/81448 PR c/81306 * c-warn.c (warn_for_multistatement_macros): Prevent bogus warnings. Avoid walking MACRO_MAP_LOCATIONS. * c-c++-common/Wmultistatement-macros-13.c: New test. Added: branches/range-gen2/gcc/testsuite/c-c++-common/Wmultistatement-macros-13.c Modified: branches/range-gen2/gcc/c-family/c-warn.c branches/range-gen2/gcc/c/ChangeLog branches/range-gen2/gcc/testsuite/ChangeLog
[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448 --- Comment #11 from Marek Polacek --- Cool, thanks for confirming.
[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448 --- Comment #10 from Bernd Edlinger --- Confirmed. Thanks!
[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448 Marek Polacek changed: What|Removed |Added Status|ASSIGNED|RESOLVED Resolution|--- |FIXED --- Comment #9 from Marek Polacek --- Hopefully fixed.
[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448 --- Comment #8 from Marek Polacek --- Author: mpolacek Date: Wed Aug 2 11:56:54 2017 New Revision: 250822 URL: https://gcc.gnu.org/viewcvs?rev=250822=gcc=rev Log: PR c/81448 PR c/81306 * c-warn.c (warn_for_multistatement_macros): Prevent bogus warnings. Avoid walking MACRO_MAP_LOCATIONS. * c-c++-common/Wmultistatement-macros-13.c: New test. Added: trunk/gcc/testsuite/c-c++-common/Wmultistatement-macros-13.c Modified: trunk/gcc/c-family/c-warn.c trunk/gcc/c/ChangeLog trunk/gcc/testsuite/ChangeLog
[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448 Marek Polacek changed: What|Removed |Added Status|NEW |ASSIGNED Assignee|unassigned at gcc dot gnu.org |mpolacek at gcc dot gnu.org
[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448
Marek Polacek changed:
What|Removed |Added
Status|UNCONFIRMED |NEW
Last reconfirmed||2017-07-26
Ever confirmed|0 |1
--- Comment #7 from Marek Polacek ---
I think this is a real bug now:
void baz (void);
#define FOO for (int i = 0; i < 10; i++)
#define BAR \
void bar (void) \
{ \
FOO \
baz (); \
return; \
}
BAR
the warning is fooled because the "body" (baz();) and "next" are coming from
the same expansion, and "guard" isn't.
[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448
--- Comment #6 from Bernd Edlinger ---
(In reply to Marek Polacek from comment #5)
> PR81364 is fixed, do you still see any false positives?
Well adding braces would fix the warning,
but consider this slightly reduced test case:
void b_ecb_encrypt();
#define BLOCK_CIPHER_ecb_loop() \
int i, bl; \
bl = 100; \
if (inl < bl) return 1; \
inl -= bl; \
for (i=0; i <= inl; i+=bl)
#define BLOCK_CIPHER_func_ecb(cname, cprefix, kstruct, ksched) \
int cname##_ecb_cipher(char *out, char *in, int inl) \
{ \
BLOCK_CIPHER_ecb_loop() \
cprefix##_ecb_encrypt(in + i, out + i); \
return 1; \
}
BLOCK_CIPHER_func_ecb(a,b,c,d)
int test(unsigned char *out, const unsigned char *in, int inl)
{
BLOCK_CIPHER_ecb_loop()
b_ecb_encrypt(in + i, out + i);
return 1;
}
Why is the warning only in the macro expansion
and not in explicit instantiation ?
[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448 --- Comment #5 from Marek Polacek --- PR81364 is fixed, do you still see any false positives?
[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448
--- Comment #4 from Bernd Edlinger ---
(In reply to Marek Polacek from comment #3)
> Guess we'll need the PR81364 fix for that.
Yes, although it would be good to require
a "{" only if cprefix##_ecb_encrypt(...) actually expands
to multiple stmts, if it expands to single stmt as here
BLOCK_CIPHER_ecb_loop() would be usable like for(;;)
[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448 --- Comment #3 from Marek Polacek --- Guess we'll need the PR81364 fix for that.
[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448
--- Comment #2 from Bernd Edlinger ---
Not really:
diff --git a/crypto/evp/evp_locl.h b/crypto/evp/evp_locl.h
index 2bb709a..cb44ed8 100644
--- a/crypto/evp/evp_locl.h
+++ b/crypto/evp/evp_locl.h
@@ -71,8 +71,9 @@
#define BLOCK_CIPHER_func_ecb(cname, cprefix, kstruct, ksched) \
static int cname##_ecb_cipher(EVP_CIPHER_CTX *ctx, unsigned char *out, const
unsigned char *in, size_t inl) \
{\
-BLOCK_CIPHER_ecb_loop() \
+BLOCK_CIPHER_ecb_loop() { \
cprefix##_ecb_encrypt(in + i, out + i, &((kstruct
*)ctx->cipher_data)->ksched, ctx->encrypt);\
+} \
return 1;\
}
In file included from e_bf.c:63:0:
e_bf.c: In function 'bf_ecb_cipher':
evp_locl.h:74:33: error: macro expands to multiple statements
[-Werror=multistatement-macros]
BLOCK_CIPHER_ecb_loop() { \
^
evp_locl.h:132:9: note: in expansion of macro 'BLOCK_CIPHER_func_ecb'
BLOCK_CIPHER_func_ecb(cname, cprefix, kstruct, ksched) \
^
evp_locl.h:251:9: note: in expansion of macro 'BLOCK_CIPHER_all_funcs'
BLOCK_CIPHER_all_funcs(cname, cprefix, cbits, kstruct, ksched) \
^~
e_bf.c:76:1: note: in expansion of macro 'IMPLEMENT_BLOCK_CIPHER'
IMPLEMENT_BLOCK_CIPHER(bf, ks, BF, EVP_BF_KEY, NID_bf, 8, 16, 8, 64,
^~
evp_locl.h:69:9: note: some parts of macro expansion are not guarded by this
'for' clause
for(i=0; i <= inl; i+=bl)
^~~
evp_locl.h:74:9: note: in expansion of macro 'BLOCK_CIPHER_ecb_loop'
BLOCK_CIPHER_ecb_loop() { \
^
evp_locl.h:132:9: note: in expansion of macro 'BLOCK_CIPHER_func_ecb'
BLOCK_CIPHER_func_ecb(cname, cprefix, kstruct, ksched) \
^
evp_locl.h:251:9: note: in expansion of macro 'BLOCK_CIPHER_all_funcs'
BLOCK_CIPHER_all_funcs(cname, cprefix, cbits, kstruct, ksched) \
^~
e_bf.c:76:1: note: in expansion of macro 'IMPLEMENT_BLOCK_CIPHER'
IMPLEMENT_BLOCK_CIPHER(bf, ks, BF, EVP_BF_KEY, NID_bf, 8, 16, 8, 64,
^~
[Bug c/81448] False positive -Werror=multistatement-macros in openssl
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81448
Marek Polacek changed:
What|Removed |Added
CC||mpolacek at gcc dot gnu.org
--- Comment #1 from Marek Polacek ---
To me it seems the warning is doing what it should here, simply wrapping the
body of the for loop into {} should fix it.
