Add coverage mapping generation.

This patch adds the '-fcoverage-mapping' option which
allows clang to generate the coverage mapping information
that can be used to provide code coverage analysis using
the execution counts obtained from the instrumentation 
based profiling (-fprofile-instr-generate).

llvm-svn: 214752
diff --git a/clang/lib/Frontend/CompilerInvocation.cpp b/clang/lib/Frontend/CompilerInvocation.cpp
index 0c6d77d..0fbbf1a 100644
--- a/clang/lib/Frontend/CompilerInvocation.cpp
+++ b/clang/lib/Frontend/CompilerInvocation.cpp
@@ -403,6 +403,7 @@
   Opts.SampleProfileFile = Args.getLastArgValue(OPT_fprofile_sample_use_EQ);
   Opts.ProfileInstrGenerate = Args.hasArg(OPT_fprofile_instr_generate);
   Opts.InstrProfileInput = Args.getLastArgValue(OPT_fprofile_instr_use_EQ);
+  Opts.CoverageMapping = Args.hasArg(OPT_fcoverage_mapping);
   Opts.AsmVerbose = Args.hasArg(OPT_masm_verbose);
   Opts.ObjCAutoRefCountExceptions = Args.hasArg(OPT_fobjc_arc_exceptions);
   Opts.CUDAIsDevice = Args.hasArg(OPT_fcuda_is_device);