README.coverage

   The clang/llvm tool set generates two kinds of coverage information:
A. Clang generates default.profraw files; apparently this is designed for integration with Xcode projects.
     The command line options are
	CFLAGS+=-fprofile-instr-generate -fcoverage-mapping
	LDFLAGS+=-fprofile-instr-generate -fcoverage-mapping
  We do not utilize this style of coverage. "rvpmake MKCOVERAGE2=yes" will generate the 'prof' files	
B. Clang/llvm also can generate information roughly compatible with GCC code coverage tools.
     The command line options are (rvpmake MKCOVERAGE=yes inserts these command line options)
	CFLAGS+=--coverage -g
	#    I don't know what LDFLAGS should be - this is overkill, probably
	LDFLAGS+=--coverage -fprofile-instr-generate -fcoverage-mapping
     The compiler generates a .gcno file for each .c file. During execution a .gcda file is created/updated with 
   usuage counts. Additional runs add to the totals in the .gcda file. The llvm-cov gcov utility creates human
   readable .gcov files.
     There are many GCC tools like lcov that analyze/summerize/display .gcov files, but the clang files 
   are not compatible for some reason.

Example
  Create coverage information on the rv-predict runtime:
        cd ~/rv-predict
        rvpmake cleandir
        rvpmake MKCOVERAGE=yes
        do.run4cov
        cd llvm/ngrt
        llvm-cov gcov *.c

        There will now be *.c.gcov and *.h.gcov files that show the source and execution counts line by line.