[cfe-dev] Getting started with the LLVM static analyzer

[Marshall Clow]

Hello all --

Wrote myself a little C file to try out the static analyzer.  (Mac OS X 10.6.4, Xcode 3.2.2, etc)

> #include <stdio.h>
> 
> int read_ptr ( int * ptr ) {
> 	int ret = *ptr;
> 	
> 	if ( ptr == NULL )
> 		return -1;
> 	return ret;
> 	}
> 
> int read_ptr2 ( int *ptr ) {
> 	int ret;
> 	if ( ptr != NULL )
> 		ret = *ptr;
> 	return ret;
> 	}
> 
> int main ( int argc, char *argv [] ) {
> 	int aVal = 12345;
> 	
> 	printf ( "12345 = %d\n", read_ptr ( &aVal ));
> 	printf ( "NULL = %d\n",  read_ptr ( NULL ));
> 
> 	printf ( "12345 = %d\n", read_ptr2 ( &aVal ));
> 	printf ( "NULL = %d\n",  read_ptr2 ( NULL ));
> 	return 0;
> 	}
> 	
	
Looked at the web page (getting started) <http://clang-analyzer.llvm.org/scan-build.html> saw:
> Basic usage of scan-build is designed to be simple: just place the word "scan-build" in front of your build command:

So I tried: 

$ /Marshall/Sources/llvm/tools/clang/tools/scan-build/scan-build clang null_check.c 
> -bash: scan-build: command not found129-46-76-102:mtc-tests marshall$ /Marshall/Sources/llvm/tools/clang/tools/scan-build/scan-build clang null_check.c 
> scan-build: 'clang' executable not found in '/Marshall/Sources/llvm/tools/clang/tools/scan-build/bin'.
> scan-build: Using 'clang' from path: /usr/bin/clang
> scan-build: Removing directory '/var/folders/X6/X6xeSru7EZ0ErJlIXsBQxE+++TI/-Tmp-/scan-build-2010-10-13-1' because it contains no reports.


Well, crap - that's not what I wanted; I want to use the clang I just built.

Try again:

$ /Marshall/Sources/llvm/tools/clang/tools/scan-build/scan-build /Marshall/Sources/llvm/Debug+Asserts/bin/clang null_check.c 
> scan-build: 'clang' executable not found in '/Marshall/Sources/llvm/tools/clang/tools/scan-build/bin'.
> scan-build: Using 'clang' from path: /usr/bin/clang
> scan-build: Removing directory '/var/folders/X6/X6xeSru7EZ0ErJlIXsBQxE+++TI/-Tmp-/scan-build-2010-10-13-1' because it contains no reports.


Third try: [ I moved /usr/bin to the end of my $PATH, and put /Marshall/Sources/llvm/Debug+Asserts/bin/clang before it. ]

$ /Marshall/Sources/llvm/tools/clang/tools/scan-build/scan-build /Marshall/Sources/llvm/Debug+Asserts/bin/clang null_check.c 
> scan-build: 'clang' executable not found in '/Marshall/Sources/llvm/tools/clang/tools/scan-build/bin'.
> scan-build: Using 'clang' from path: /Marshall/Sources/llvm/Debug+Asserts/bin/clang
> scan-build: Removing directory '/var/folders/X6/X6xeSru7EZ0ErJlIXsBQxE+++TI/-Tmp-/scan-build-2010-10-13-1' because it contains no reports.

Does the scan-build tool not work with "naked" clang commands?

So I built a makefile:

> CC=/Marshall/Sources/llvm/Debug+Asserts/bin/clang
> 
> null_check: null_check.o
> 
> clean:
> 	rm -f null_check null_check.o
> 

and verified that it worked, and tried:

$ /Marshall/Sources/llvm/tools/clang/tools/scan-build/scan-build make
> scan-build: 'clang' executable not found in '/Marshall/Sources/llvm/tools/clang/tools/scan-build/bin'.
> scan-build: Using 'clang' from path: /usr/bin/clang
> /Marshall/Sources/llvm/Debug+Asserts/bin/clang    -c -o null_check.o null_check.c
> /Marshall/Sources/llvm/Debug+Asserts/bin/clang   null_check.o   -o null_check
> scan-build: Removing directory '/var/folders/X6/X6xeSru7EZ0ErJlIXsBQxE+++TI/-Tmp-/scan-build-2010-10-13-1' because it contains no reports.


So now, I'm using the clang that I want (I think) - but I'm getting no reports. Char's up with that?
What am I missing? (the LLVM and clang were checked out fresh this morning from SVN).

Thanks in advance!

-- Marshall
Qualcomm, Inc.