[llvm-cov] Add some documentation for the -tab-size option

Also, un-hide the cl::opt.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277741 91177308-0d34-0410-b5e6-96231b3b80d8

docs/CommandGuide/llvm-cov.rst

@@ -241,6 +241,11 @@ OPTIONS
 
  Use the specified output format. The supported formats are: "text", "html".
 
+.. option:: -tab-size=<TABSIZE>
+
+ Replace tabs with <TABSIZE> spaces when preparing reports. Currently, this is
+ only supported for the html format.
+
 .. option:: -output-dir=PATH
 
  Specify a directory to write coverage reports into. If the directory does not

tools/llvm-cov/CodeCoverage.cpp

@@ -585,8 +585,9 @@ int CodeCoverageTool::show(int argc, const char **argv,
                                  cl::aliasopt(ShowOutputDirectory));
 
   cl::opt<uint32_t> TabSize(
-      "tab-size", cl::Hidden, cl::init(2),
-      cl::desc("Set tab size for the HTML coverage report (default = 2)"));
+      "tab-size", cl::init(2),
+      cl::desc(
+          "Set tab expansion size for html coverage reports (default = 2)"));
 
   auto Err = commandLineParser(argc, argv);
   if (Err)