Bug 735515
| Summary: | libvirt doesn't compile under clang, because of configure hanging on btowc(0) check | ||
|---|---|---|---|
| Product: | [Community] Virtualization Tools | Reporter: | Aleksander Balicki <balicki.aleksander> |
| Component: | libvirt | Assignee: | Eric Blake <eblake> |
| Status: | CLOSED CANTFIX | QA Contact: | |
| Severity: | unspecified | Docs Contact: | |
| Priority: | unspecified | ||
| Version: | unspecified | CC: | crobinso, eblake, xen-maint |
| Target Milestone: | --- | ||
| Target Release: | --- | ||
| Hardware: | i686 | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | Bug Fix | |
| Doc Text: | Story Points: | --- | |
| Clone Of: | Environment: | ||
| Last Closed: | 2011-09-03 02:55:31 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
This sounds like a gnulib problem that will impact multiple source packages. Can you please send email to bug-gnulib describing the issues, and give the details from the conversation on #llvm why you think it is a configure bug? 19:10:35 alistra_> i have another gcc/clang mismatch, libvirt-0.9.{3,4} hangs on configure on the line checking whether btowc(0) is correct...
19:10:56 alistra_> clang hangs and gcc goes thru
19:11:33 echristo> yeah, it's a wonky configure program that abuses inline
sorry for the compactness, but it's the only info i got
Which versions of gcc and clang? And can you send this to bug-gnulib? it was checked with clang-2.9 and trunk - the same effect it compiles under gcc-4.4.5 According to the gnulib folks [1], this is either a bug in the glibc header for using non-portable __asm and expecting non-gcc to understand it, or a bug in clang for pretending to be gcc but not understanding __asm in the same was as gcc. There is nothing libvirt can do about either of those situations, so I'm closing this bug as CANTFIX. [1] https://lists.gnu.org/archive/html/bug-gnulib/2011-09/msg00027.html > I guess that clang hangs or produces an endless loop because of > this inline definition in <wchar.h>: > > extern wint_t __btowc_alias (int __c) __asm ("btowc"); > __extern_inline wint_t > __NTH (btowc (int __c)) > { return (__builtin_constant_p (__c) && __c >= '\0' && __c <= '\x7f' > ? (wint_t) __c : __btowc_alias (__c)); } > > Evidently, clang gives a different semantics to __asm than GCC. > But GCC's semantics of __asm is fixed for 20 years. > > Conclusion: Needs to be fixed in clang. By the way, clang clang-2.8-12.fc14.x86_64 compiled things just fine for me on Fedora 14. |
Description of problem: libvirt doesn't compile under clang it doesn't even finish configure it hangs forever on the btowc(0) check on gcc it goes thru after conversation on #llvm got info, that's probably the fault of configure abusing inline. Version-Release number of selected component (if applicable): 0.9.{3,4} How reproducible: always Steps to Reproduce: 1.compile on gentoo USE=virt-network CC=clang CXX=clang++ emerge -1 libvirt Actual results: hangs on the line: checking btowc(0) Expected results: go thru with configure and compilation Additional info: