for casual use. Usage: (1) assign {} to COVERAGE__, (2) require or
load Ruby source file, and (3) COVERAGE__["sourcefilepath"] will
return an array whose elements represent number of executions per
line of source code.
* vm_core.h: add field of coverage array to iseq.
* iseq.c (prepare_iseq_build): ditto.
* insns.def (trace): update coverage array.
* parse.y (coverage): create and initialize coverage array.
* compile.h (ADD_TRACE): add trace instruction to update covearge
array.
* thread.c (clear_coverage): delete coverage array when forking.
Otherwise, double count of coverage may occur.
* lib/coverage.rb: sample coverage measurement tool.
* error.c: distinguish explicitly between parse_in_eval and
mild_compile_error.
* load.c: ditto.
* vm_eval.c: ditto.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@17781 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
