sparse - Fixing build warnings - linux-kernel

Question

I'm compiling the sparse - linux kernel checking tool.
But it throws the following warning:
lovegcy#knltest-VirtualBox:~/git_root/sparse$ make
GEN version.h
/bin/sh: 1: llvm-config: not found
Makefile:63: Your system does not have libxml, disabling c2xml
Makefile:75: Your system does not have libgtk2, disabling test-inspect
Makefile:79: Your system does not have llvm, disabling sparse-llvm
CC test-lexing.o
CC target.o
CC parse.o
CC tokenize.o
CC pre-process.o
CC symbol.o
CC lib.o
CC scope.o
CC expression.o
CC show-parse.o
CC evaluate.o
CC expand.o
CC inline.o
CC linearize.o
CC char.o
CC sort.o
CC allocate.o
CC compat-linux.o
CC ptrlist.o
CC flow.o
CC cse.o
CC simplify.o
CC memops.o
CC liveness.o
CC storage.o
CC unssa.o
CC dissect.o
AR libsparse.a
LINK test-lexing
CC test-parsing.o
LINK test-parsing
CC obfuscate.o
LINK obfuscate
CC compile.o
CC compile-i386.o
compile-i386.c: In function ‘emit_insn_atom’:
compile-i386.c:719:7: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result]
LINK compile
CC graph.o
LINK graph
CC sparse.o
LINK sparse
CC test-linearize.o
LINK test-linearize
CC example.o
LINK example
CC test-unssa.o
LINK test-unssa
CC test-dissect.o
LINK test-dissect
CC ctags.o
LINK ctags
GEN sparse.pc
Fix the following
Makefile:63: Your system does not have libxml, disabling c2xml
Makefile:75: Your system does not have libgtk2, disabling test-inspect
by:
$ sudo apt-get install libxml2-dev libgtk2.0-dev
For
/bin/sh: 1: llvm-config: not found
Makefile:79: Your system does not have llvm, disabling sparse-llvm
the llvm-3.2-dev is installed, but it is still there.
I still donot know how to fix the following warning too:
compile-i386.c: In function ‘emit_insn_atom’:
compile-i386.c:719:7: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result]
Could anyone give some suggestions?
Thank you very much!
Update : Following TheCodeArtist's suggestion, here is the build error log after llvm installed.
lovegcy#knltest-VirtualBox:~/git_root/sparse$ make
CC test-lexing.o
CC target.o
CC parse.o
CC tokenize.o
CC pre-process.o
CC symbol.o
CC lib.o
CC scope.o
CC expression.o
CC show-parse.o
CC evaluate.o
CC expand.o
CC inline.o
CC linearize.o
CC char.o
CC sort.o
CC allocate.o
CC compat-linux.o
CC ptrlist.o
CC flow.o
CC cse.o
CC simplify.o
CC memops.o
CC liveness.o
CC storage.o
CC unssa.o
CC dissect.o
AR libsparse.a
LINK test-lexing
CC test-parsing.o
LINK test-parsing
CC obfuscate.o
LINK obfuscate
CC compile.o
CC compile-i386.o
compile-i386.c: In function ‘emit_insn_atom’:
compile-i386.c:719:7: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result]
LINK compile
CC graph.o
LINK graph
CC sparse.o
LINK sparse
CC test-linearize.o
LINK test-linearize
CC example.o
LINK example
CC test-unssa.o
LINK test-unssa
CC test-dissect.o
LINK test-dissect
CC ctags.o
LINK ctags
CC c2xml.o
LINK c2xml
CC test-inspect.o
CC ast-model.o
CC ast-view.o
CC ast-inspect.o
LINK test-inspect
CC sparse-llvm.o
LINK sparse-llvm
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(Signals.o): In function PrintStackTrace(void*)':
(.text+0x74): undefined reference todladdr'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(Signals.o): In function PrintStackTrace(void*)':
(.text+0x1fe): undefined reference todladdr'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(Mutex.o): In function llvm::sys::MutexImpl::MutexImpl(bool)':
(.text+0x58): undefined reference topthread_mutexattr_init'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(Mutex.o): In function llvm::sys::MutexImpl::MutexImpl(bool)':
(.text+0x64): undefined reference topthread_mutexattr_settype'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(Mutex.o): In function llvm::sys::MutexImpl::MutexImpl(bool)':
(.text+0x74): undefined reference topthread_mutexattr_setpshared'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(Mutex.o): In function llvm::sys::MutexImpl::MutexImpl(bool)':
(.text+0x88): undefined reference topthread_mutexattr_destroy'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(Mutex.o): In function llvm::sys::MutexImpl::tryacquire()':
(.text+0x179): undefined reference topthread_mutex_trylock'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(RWMutex.o): In function llvm::sys::RWMutexImpl::RWMutexImpl()':
(.text+0x3e): undefined reference topthread_rwlock_init'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(RWMutex.o): In function llvm::sys::RWMutexImpl::~RWMutexImpl()':
(.text+0x80): undefined reference topthread_rwlock_destroy'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(RWMutex.o): In function llvm::sys::RWMutexImpl::reader_acquire()':
(.text+0xb9): undefined reference topthread_rwlock_rdlock'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(RWMutex.o): In function llvm::sys::RWMutexImpl::reader_release()':
(.text+0xe9): undefined reference topthread_rwlock_unlock'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(RWMutex.o): In function llvm::sys::RWMutexImpl::writer_acquire()':
(.text+0x119): undefined reference topthread_rwlock_wrlock'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(RWMutex.o): In function llvm::sys::RWMutexImpl::writer_release()':
(.text+0x149): undefined reference topthread_rwlock_unlock'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(ThreadLocal.o): In function llvm::sys::ThreadLocalImpl::~ThreadLocalImpl()':
(.text+0x25): undefined reference topthread_key_delete'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(ThreadLocal.o): In function llvm::sys::ThreadLocalImpl::ThreadLocalImpl()':
(.text+0xae): undefined reference topthread_key_create'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(ThreadLocal.o): In function llvm::sys::ThreadLocalImpl::setInstance(void const*)':
(.text+0xe2): undefined reference topthread_setspecific'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(ThreadLocal.o): In function llvm::sys::ThreadLocalImpl::getInstance()':
(.text+0x10a): undefined reference topthread_getspecific'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(Threading.o): In function llvm::llvm_execute_on_thread(void (*)(void*), void*, unsigned int)':
(.text+0x1c2): undefined reference topthread_create'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(Threading.o): In function llvm::llvm_execute_on_thread(void (*)(void*), void*, unsigned int)':
(.text+0x1da): undefined reference topthread_join'
/usr/lib/llvm-3.2/lib/libLLVMSupport.a(Threading.o): In function llvm::llvm_execute_on_thread(void (*)(void*), void*, unsigned int)':
(.text+0x20c): undefined reference topthread_attr_setstacksize'
collect2: error: ld returned 1 exit status
make: * [sparse-llvm] Error 1

Answer 1

Properly installing llvm :
During the build, for make to detect llvm on the system ,llvm-config is required to be installed on your system properly. On Ubuntu, the following command will download(~16MB packages) and install all the dependencies correctly
$ sudo apt-get install llvm
Download the latest source of sparse
$ git clone git://git.kernel.org/pub/scm/devel/sparse/sparse.git
Build and install sparse
$ cd sparse
$ make
$ make install
(Tested on Ubuntu 10.04)
Fixing the innocuous Warning :
The following error is harmless in the current context as we are not concerned with the result of the call to write() at line 719 of compile-i386.c
compile-i386.c:719:7: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result]
Fixing this error is as simple as modifying line 719 of compile-i386.c to
comment[0] = write(STDOUT_FILENO, s, strlen(s));
This warning is triggered during build due to the -Wall (Enable ALL warnings) flag passed to gcc at line 16 of the Makefile
CFLAGS += -Wall -Wwrite-strings