Il 22/06/2013 12:03, Stefan Weil ha scritto:
Am 18.06.2013 12:13, schrieb Paolo Bonzini:
Il 07/06/2013 14:17, Markus Armbruster ha scritto:
diff --git a/util/iov.c b/util/iov.c
index cc6e837..b91cfb9 100644
--- a/util/iov.c
+++ b/util/iov.c
@@ -146,7 +146,7 @@ ssize_t iov_send_recv(int sockfd, struct iovec *iov,
unsigned iov_cnt,
{
ssize_t total = 0;
ssize_t ret;
- size_t orig_len, tail;
+ size_t orig_len = 0, tail;
unsigned niov;
while (bytes > 0) {
Here are the uses of orig_len:
if (tail) {
/* second, fixup the last element, and remember the original
* length */
assert(niov < iov_cnt);
assert(iov[niov].iov_len > tail);
orig_len = iov[niov].iov_len;
iov[niov++].iov_len = tail;
}
ret = do_send_recv(sockfd, iov, niov, do_send);
/* Undo the changes above before checking for errors */
if (tail) {
iov[niov-1].iov_len = orig_len;
}
I get this warning, too, when I run a normal cross compilation with
MinGW-w64:
util/iov.c:190:33: warning: ‘orig_len’ may be used uninitialized in this
function [-Wuninitialized]
My build environment:
Debian wheezy with packages gcc-mingw-w64-i686, gcc-mingw-w64-x86-64
(4.6.3-14+8).
A complete build results in 5 warnings. Here are the other 4 of them:
hw/arm/spitz.c:280:0: warning: "MOD_SHIFT" redefined [enabled by default]
hw/ppc/spapr.c:673:26: warning: cast from pointer to integer of
different size [-Wpointer-to-int-cast]
Isn't this one a Win64 bug?
hw/ppc/spapr_hcall.c:188:1: warning: control reaches end of non-void
function [-Wreturn-type]
hw/ppc/spapr_pci.c:454:1: warning: control reaches end of non-void
function [-Wreturn-type]
I think you could report this to mingw. GCC should handle "if (!0)
foo()" just fine if foo is noreturn, perhaps the "assertion failure"
runtime function is not noreturn in mingw.
I already sent a patch for the MOD_SHIFT issue.
The remaining 3 warnings are also caused by code which makes it difficult
for the compiler to detect that it is correct.
Not as hard as this one, though.
Anyway, I would be okay a fix that makes the code easier to follow for
compilers (and doesn't have too much duplication so that humans are also
happy). But adding "= 0" is the worst, because smart compilers will not
detect a human's mistakes anymore.
Paolo