[systemd-commits] 3 commits - src/resolve src/shared src/test
David Herrmann
dvdhrm at kemper.freedesktop.org
Fri Aug 15 07:59:59 PDT 2014
src/resolve/resolved-dns-stream.c | 2 -
src/resolve/resolved-manager.c | 2 -
src/shared/macro.h | 61 +++++++++++++++++++++-----------------
src/test/test-util.c | 23 ++++++++++++++
4 files changed, 60 insertions(+), 28 deletions(-)
New commits:
commit bf32f99f65ec42539af65736b057c9e09d3987b9
Author: David Herrmann <dh.herrmann at gmail.com>
Date: Fri Aug 15 16:58:16 2014 +0200
resolve: fix compilation on LLVM+clang
LLVM+clang does not allow statement-expressions inside of
type-declarations (file-scope). Use CONST_MAX() to avoid this.
diff --git a/src/resolve/resolved-dns-stream.c b/src/resolve/resolved-dns-stream.c
index eb78587..8b3a3ce 100644
--- a/src/resolve/resolved-dns-stream.c
+++ b/src/resolve/resolved-dns-stream.c
@@ -64,7 +64,7 @@ static int dns_stream_complete(DnsStream *s, int error) {
static int dns_stream_identify(DnsStream *s) {
union {
struct cmsghdr header; /* For alignment */
- uint8_t buffer[CMSG_SPACE(MAX(sizeof(struct in_pktinfo), sizeof(struct in6_pktinfo)))
+ uint8_t buffer[CMSG_SPACE(CONST_MAX(sizeof(struct in_pktinfo), sizeof(struct in6_pktinfo)))
+ EXTRA_CMSG_SPACE /* kernel appears to require extra space */];
} control;
struct msghdr mh = {};
diff --git a/src/resolve/resolved-manager.c b/src/resolve/resolved-manager.c
index bfbdc7d..04ee204 100644
--- a/src/resolve/resolved-manager.c
+++ b/src/resolve/resolved-manager.c
@@ -841,7 +841,7 @@ int manager_recv(Manager *m, int fd, DnsProtocol protocol, DnsPacket **ret) {
_cleanup_(dns_packet_unrefp) DnsPacket *p = NULL;
union {
struct cmsghdr header; /* For alignment */
- uint8_t buffer[CMSG_SPACE(MAX(sizeof(struct in_pktinfo), sizeof(struct in6_pktinfo)))
+ uint8_t buffer[CMSG_SPACE(CONST_MAX(sizeof(struct in_pktinfo), sizeof(struct in6_pktinfo)))
+ CMSG_SPACE(int) /* ttl/hoplimit */
+ EXTRA_CMSG_SPACE /* kernel appears to require extra buffer space */];
} control;
commit 7242d7420b04132f93f1426ec713f9b09bdeba54
Author: David Herrmann <dh.herrmann at gmail.com>
Date: Fri Aug 15 16:54:52 2014 +0200
macro: add CONST_MAX() macro
The CONST_MAX() macro is similar to MAX(), but verifies that both
arguments have the same type and are constant expressions. Furthermore,
the result of CONST_MAX() is again a constant-expression.
CONST_MAX() avoids any statement-expressions and other non-trivial
expression-types. This avoids rather arbitrary restrictions in both GCC
and LLVM, which both either fail with statement-expressions inside
type-declarations or statement-expressions inside static-const
initializations.
If anybody knows how to circumvent this, please feel free to unify
CONST_MAX() and MAX().
diff --git a/src/shared/macro.h b/src/shared/macro.h
index 11bd8b3..179b24c 100644
--- a/src/shared/macro.h
+++ b/src/shared/macro.h
@@ -140,6 +140,15 @@ static inline unsigned long ALIGN_POWER2(unsigned long u) {
_a > _b ? _a : _b; \
})
+/* evaluates to (void) if _A or _B are not constant or of different types */
+#define CONST_MAX(_A, _B) \
+ __extension__ (__builtin_choose_expr( \
+ __builtin_constant_p(_A) && \
+ __builtin_constant_p(_B) && \
+ __builtin_types_compatible_p(typeof(_A), typeof(_B)), \
+ ((_A) > (_B)) ? (_A) : (_B), \
+ (void)0))
+
#define MAX3(x,y,z) \
__extension__ ({ \
const typeof(x) _c = MAX(x,y); \
diff --git a/src/test/test-util.c b/src/test/test-util.c
index 7d81b0b..a8fa48a 100644
--- a/src/test/test-util.c
+++ b/src/test/test-util.c
@@ -70,6 +70,28 @@ static void test_align_power2(void) {
}
}
+static void test_max(void) {
+ static const struct {
+ int a;
+ int b[CONST_MAX(10, 100)];
+ } val1 = {
+ .a = CONST_MAX(10, 100),
+ };
+ int d = 0;
+
+ assert_cc(sizeof(val1.b) == sizeof(int) * 100);
+
+ /* CONST_MAX returns (void) instead of a value if the passed arguments
+ * are not of the same type or not constant expressions. */
+ assert_cc(__builtin_types_compatible_p(typeof(CONST_MAX(1, 10)), int));
+ assert_cc(__builtin_types_compatible_p(typeof(CONST_MAX(d, 10)), void));
+ assert_cc(__builtin_types_compatible_p(typeof(CONST_MAX(1, 1U)), void));
+
+ assert_se(val1.a == 100);
+ assert_se(MAX(++d, 0) == 1);
+ assert_se(d == 1);
+}
+
static void test_first_word(void) {
assert_se(first_word("Hello", ""));
assert_se(first_word("Hello", "Hello"));
@@ -927,6 +949,7 @@ int main(int argc, char *argv[]) {
test_streq_ptr();
test_align_power2();
+ test_max();
test_first_word();
test_close_many();
test_parse_boolean();
commit fdcba430aeae442ab0ea12a08d96cfc3d13f57ef
Author: David Herrmann <dh.herrmann at gmail.com>
Date: Fri Aug 15 16:16:30 2014 +0200
macro: const'ify MIN/MAX/... macros
We must add 'const' to local variables in statement-expressions to
guarantee that the macros can produce constant-expressions if given such.
GCC seems to ignore this, but LLVM/clang requires it (understandably).
diff --git a/src/shared/macro.h b/src/shared/macro.h
index 5619c32..11bd8b3 100644
--- a/src/shared/macro.h
+++ b/src/shared/macro.h
@@ -133,46 +133,46 @@ static inline unsigned long ALIGN_POWER2(unsigned long u) {
})
#undef MAX
-#define MAX(a,b) \
- __extension__ ({ \
- typeof(a) _a = (a); \
- typeof(b) _b = (b); \
- _a > _b ? _a : _b; \
+#define MAX(a,b) \
+ __extension__ ({ \
+ const typeof(a) _a = (a); \
+ const typeof(b) _b = (b); \
+ _a > _b ? _a : _b; \
})
-#define MAX3(x,y,z) \
- __extension__ ({ \
- typeof(x) _c = MAX(x,y); \
- MAX(_c, z); \
+#define MAX3(x,y,z) \
+ __extension__ ({ \
+ const typeof(x) _c = MAX(x,y); \
+ MAX(_c, z); \
})
#undef MIN
-#define MIN(a,b) \
- __extension__ ({ \
- typeof(a) _a = (a); \
- typeof(b) _b = (b); \
- _a < _b ? _a : _b; \
+#define MIN(a,b) \
+ __extension__ ({ \
+ const typeof(a) _a = (a); \
+ const typeof(b) _b = (b); \
+ _a < _b ? _a : _b; \
})
-#define MIN3(x,y,z) \
- __extension__ ({ \
- typeof(x) _c = MIN(x,y); \
- MIN(_c, z); \
+#define MIN3(x,y,z) \
+ __extension__ ({ \
+ const typeof(x) _c = MIN(x,y); \
+ MIN(_c, z); \
})
-#define LESS_BY(A,B) \
- __extension__ ({ \
- typeof(A) _A = (A); \
- typeof(B) _B = (B); \
- _A > _B ? _A - _B : 0; \
+#define LESS_BY(A,B) \
+ __extension__ ({ \
+ const typeof(A) _A = (A); \
+ const typeof(B) _B = (B); \
+ _A > _B ? _A - _B : 0; \
})
#ifndef CLAMP
#define CLAMP(x, low, high) \
__extension__ ({ \
- typeof(x) _x = (x); \
- typeof(low) _low = (low); \
- typeof(high) _high = (high); \
+ const typeof(x) _x = (x); \
+ const typeof(low) _low = (low); \
+ const typeof(high) _high = (high); \
((_x > _high) ? _high : ((_x < _low) ? _low : _x)); \
})
#endif
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