[llvm-cov] Avoid 0% when reporting something that's 0/0

This commit makes llvm-cov avoid showing 0% (0/0) coverage for things
like file function coverage, etc. in reports and HTML output. This can happen
for files like headers that have macros but no functions. This commit makes
llvm-cov report - (0/0) instead.

rdar://29246480

Differential Revision: https://reviews.llvm.org/D26615

llvm-svn: 287539

1 files changed, 8 insertions, 4 deletions

diff --git a/llvm/tools/llvm-cov/SourceCoverageViewHTML.cpp b/llvm/tools/llvm-cov/SourceCoverageViewHTML.cpp
index 8fc01ef0d88..64b888e89d7 100644
--- a/llvm/tools/llvm-cov/SourceCoverageViewHTML.cpp
+++ b/llvm/tools/llvm-cov/SourceCoverageViewHTML.cpp
@@ -307,13 +307,17 @@ void CoveragePrinterHTML::emitFileSummary(raw_ostream &OS, StringRef SF,
     std::string S;
     {
       raw_string_ostream RSO{S};
-      RSO << format("%*.2f", 7, Pctg) << "% (" << Hit << '/' << Total << ')';
+      if (Total)
+        RSO << format("%*.2f", 7, Pctg) << "% ";
+      else
+        RSO << "- ";
+      RSO << '(' << Hit << '/' << Total << ')';
     }
     const char *CellClass = "column-entry-yellow";
-    if (Pctg < 80.0)
-      CellClass = "column-entry-red";
-    else if (Hit == Total)
+    if (Hit == Total)
       CellClass = "column-entry-green";
+    else if (Pctg < 80.0)
+      CellClass = "column-entry-red";
     Columns.emplace_back(tag("td", tag("pre", S), CellClass));
   };