[cfe-dev] linking with libclang for ios
Alp Toker
alp at nuanti.com
Mon Jul 7 01:39:01 PDT 2014
On 07/07/2014 11:14, Anton Smirnov wrote:
> Hi, Alp.
>
> 2014-07-07 12:52 GMT+06:00 Alp Toker <alp at nuanti.com
> <mailto:alp at nuanti.com>>:
>
>
> On 07/07/2014 09:24, Anton Smirnov wrote:
>
> I've started to edit Mutex.cpp and RWMutex.cpp and found it's
> not used at all if "LLVM_ENABLE_THREADS" was off during config.
> So it seems that my issues was solved with it.
>
>
> Great
>
>
> Thanks for pointing me right direction ;)
>
>
> Anyway i'm having another issue:
>
> *2014-07-07 12:19:54.090 LibClangUsage7Demo[64275:60b] started*
>
>
> *Detected an attempt to call a symbol in system libraries that
> is not present on the iPhone:*
>
> *stat$INODE64 called from function
> _ZN4llvm3sys2fs6statusERKNS_5TwineERNS1_11file_statusE in
> image LibClangUsage7Demo.*
>
>
> Is stat missing in ios simulator? It seems that i will have to
> fix such issues one-by-one..
>
> Is there any ios-friendly version of llvm/clang? Is it ios
> simulator limitations (systems calls to absent systems methods)?
>
>
> The LLVM/clang codebase is meant to be portable..
>
> So, the OS filesystem symbols are available but not implemented on
> your platform:
>
>
> What does it mean "available but not implemented"? I'm not sure i
> understand it as i have no compile/link errors, runtime errors only.
> Does it mean it has required functions declarations in headers while
> compiling, symbols while linking but absent for some reason in runtime?
> How can that be? i expect to have linker errors if required system
> calls are absent.
>
> I'm using xcode toolchain and sysroot to cross-compile for ios so i
> expect it to have valid and actual headers and compiled systems libs.
>
> What can i do to fix stat missing in llvm::sys::status(..) ? Any flags
> or change invocation to any existing system method?
>
>
> That's good news because it means there's a good chance you can
> get your application working without porting LLVM's System module.
>
>
> I'm afraid i will discover a lot of places with runtime errors (due to
> missing system libs) ;(
> Does anybody know any other expected missing/not implemented calls for
> ios?
This is a standard iOS platform? Try configuring with
-mios-simulator-version-min=7.1
>
> As I recall, you wanted to perform an in-memory compilation and
> produce LLVM IR, and I suggested using the clang-interpreter demo
> as a starting point.
>
>
> At that point i'm just trying to have actual llvm/clang working via
> Clang-C API. This means i don't have to have any major modifications,
> just cross-compile with right configure params.
>
> Probably the next step will be look into Cling modifications for
> LLVM/Clang and making it working.
Curious, what do you need the modifications for?
(Unless it's synced up to LLVM SVN very recently it'll be missing the
fixes from this discussion.)
>
> Let's take that a little further..
>
> You'll need to modify the clang-interpreter sample so it loads C
> source code for the main file from memory instead of trying to
> read from the filesystem which apparently doesn't existing on your
> platform. The code you use shouldn't include any headers or
> that'll incur filesystem access.
>
>
> Actually i can access files in ios app sandbox so i expect LLVM/Clang
> working for files in it.
Okay, should work fine if you need file access. Try the configure switch
I suggested.
>
> Meanwhile I've added non-JIT interpreter support in clang r212083,
> and if that still doesn't work you can modify the sample to print
> IR to check if things work.
>
>
> Great! How i can i try it? Any example to interpret "hello-world"?
Sure, just run:
./clang-interpreter hello.cpp
It mostly accepts the same arguments as normal clang.
Alp.
>
> With some luck it won't attempt to read from the filesystem at all
> after that, so won't hit the missing OS features.
>
> If there are more errors, we'll need to refine the approach a
> little and eliminate other kinds of file accesses but that should
> be the general angle of attack.
>
> It sounds like a fun project, keep the list posted :-)
>
>
> Well, yes it is. I'm just making proof of concept. Any help is
> appreciated.
>
>
> Alp.
>
>
>
> Regards, Anton.
>
>
>
>
> Thanks,
> Anton.
>
>
> 2014-07-06 17:16 GMT+06:00 Anton Smirnov
> <dev at antonsmirnov.name <mailto:dev at antonsmirnov.name>
> <mailto:dev at antonsmirnov.name <mailto:dev at antonsmirnov.name>>>:
>
>
> I've just tried to rebuild libclang.a
> with -miphoneos-version-min=7.0 - no luck.
> Also i've removed --enable-optimized --disable-assertions
> configure flags and it confirmed error line (Mutex.cpp):
>
> // Destroy the attributes
> errorcode = pthread_mutexattr_destroy(&attr);
>
> Should setting LLVM_ENABLE_THREADS to "off" help?
>
>
>
>
> 2014-07-06 12:03 GMT+06:00 Alp Toker <alp at nuanti.com
> <mailto:alp at nuanti.com>
> <mailto:alp at nuanti.com <mailto:alp at nuanti.com>>>:
>
>
> Did you try building with LLVM_ENABLE_THREADS off?
>
> Also consider trying ToT to get the latest fixes.
>
> Alp.
>
>
>
> On 06/07/2014 08:23, Anton Smirnov wrote:
>
> I've found Mutex.cpp file in llvm sources and it seems
> it's not the first mutex-related call in constructor.
> This makes me think it's really absent method in
> system libs:
>
> // Construct a Mutex using pthread calls
>
> MutexImpl::MutexImpl( bool recursive)
>
> : data_(0)
>
> {
>
> // Declare the pthread_mutex data structures
>
> pthread_mutex_t* mutex =
>
>
> static_cast<pthread_mutex_t*>(malloc(sizeof(pthread_mutex_t)));
>
> pthread_mutexattr_t attr;
>
>
> // Initialize the mutex attributes
>
> int errorcode = pthread_mutexattr_init(&attr);
>
> assert(errorcode == 0); (void)errorcode;
>
>
> // Initialize the mutex as a recursive mutex, if
> requested, or normal
>
> // otherwise.
>
> int kind = ( recursive ? PTHREAD_MUTEX_RECURSIVE :
> PTHREAD_MUTEX_NORMAL );
>
> errorcode = pthread_mutexattr_settype(&attr, kind);
>
> assert(errorcode == 0);
>
>
> #if !defined(__FreeBSD__) && !defined(__OpenBSD__) &&
> !defined(__NetBSD__) && \
>
> !defined(__DragonFly__) && !defined(__Bitrig__)
>
> // Make it a process local mutex
>
> errorcode = pthread_mutexattr_setpshared(&attr,
> PTHREAD_PROCESS_PRIVATE);
>
> assert(errorcode == 0);
>
> #endif
>
>
> // Initialize the mutex
>
> errorcode = pthread_mutex_init(mutex, &attr);
>
> assert(errorcode == 0);
>
>
> // Destroy the attributes
>
> errorcode = pthread_mutexattr_destroy(&attr); //
> fails here
>
> assert(errorcode == 0);
>
> // Assign the data member
> data_ = mutex;
>
> }
>
> I've marked where it fails.
> How can that be that previous mutex-related methods
> success and this one fails?
> What can i do to fix it?
>
> Regards, Anton.
>
>
> 2014-07-05 19:31 GMT+06:00 Anton Smirnov
> <dev at antonsmirnov.name
> <mailto:dev at antonsmirnov.name> <mailto:dev at antonsmirnov.name
> <mailto:dev at antonsmirnov.name>>
> <mailto:dev at antonsmirnov.name
> <mailto:dev at antonsmirnov.name>
>
> <mailto:dev at antonsmirnov.name
> <mailto:dev at antonsmirnov.name>>>>:
>
>
> Hi.
>
> I was able to cross-compile llvm/clang for
> i386 and
> i'm trying to
> use it in my ios app.
> Also i was able to add headers and static libs
> (both
> libLLVM*.a
> and libclang*.a) and compile/link the project
> with no
> errors.
>
> But when trying to run simple app i'm getting
> error:
>
> *Detected an attempt to call a symbol in system
> libraries that is
> not present on the iPhone:*
>
> *pthread_mutexattr_destroy$UNIX2003 called
> from function
> _ZN4llvm3sys9MutexImplC2Eb in image
> LibClangUsageDemo3.*
>
>
>
> What can i do in order to fix it?
>
> Is it llvm/clang issue or i'm doing smth wrong?
>
> Regards, Anton.
>
>
>
>
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