[llvm-cov] Highlight gaps in consecutive uncovered regions

llvm-cov typically doesn't highlight gap segments, but it should if the
gap occurs after an uncovered region in order to preserve continuity.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316107 91177308-0d34-0410-b5e6-96231b3b80d8

test/tools/llvm-cov/deferred-region.cpp

@@ -116,6 +116,7 @@ int main() {
 // MARKER-NEXT: Highlighted line 63, 5 -> 13
 // MARKER-NEXT: Highlighted line 67, 1 -> ?
 // MARKER-NEXT: Highlighted line 68, 1 -> 8
+// MARKER-NEXT: Highlighted line 68, 8 -> ?
 // MARKER-NEXT: Highlighted line 69, 1 -> 2
 // MARKER-NEXT: Marker at 72:7 = 2
 // MARKER-NEXT: Highlighted line 77, 1 -> 2

tools/llvm-cov/SourceCoverageViewHTML.cpp

@@ -506,7 +506,7 @@ void SourceCoverageViewHTML::renderLine(
   //    1 to set the highlight for snippet 2, segment 2 to set the highlight for
   //    snippet 3, and so on.
 
-  Optional<std::string> Color;
+  Optional<StringRef> Color;
   SmallVector<std::pair<unsigned, unsigned>, 2> HighlightedRanges;
   auto Highlight = [&](const std::string &Snippet, unsigned LC, unsigned RC) {
     if (getOptions().Debug)
@@ -528,7 +528,8 @@ void SourceCoverageViewHTML::renderLine(
     const auto *CurSeg = Segments[I];
     if (CurSeg->Col == ExpansionCol)
       Color = "cyan";
-    else if (!CurSeg->IsGapRegion && CheckIfUncovered(CurSeg))
+    else if ((!CurSeg->IsGapRegion || (Color && *Color == "red")) &&
+             CheckIfUncovered(CurSeg))
       Color = "red";
     else
       Color = None;

tools/llvm-cov/SourceCoverageViewText.cpp

@@ -121,7 +121,8 @@ void SourceCoverageViewText::renderLine(
     Col = End;
     if (Col == ExpansionCol)
       Highlight = raw_ostream::CYAN;
-    else if (!S->IsGapRegion && S->HasCount && S->Count == 0)
+    else if ((!S->IsGapRegion || Highlight == raw_ostream::RED) &&
+             S->HasCount && S->Count == 0)
       Highlight = raw_ostream::RED;
     else
       Highlight = None;