Index: test/tools/llvm-cov/Inputs/showTabsHTML.proftext
===================================================================
--- /dev/null
+++ test/tools/llvm-cov/Inputs/showTabsHTML.proftext
@@ -0,0 +1,8 @@
+main
+# Func Hash:
+0
+# Num Counters:
+1
+# Counter Values:
+1
+
Index: test/tools/llvm-cov/showTabsHTML.cpp
===================================================================
--- /dev/null
+++ test/tools/llvm-cov/showTabsHTML.cpp
@@ -0,0 +1,16 @@
+// RUN: llvm-profdata merge -o %t.profdata %S/Inputs/showTabsHTML.proftext
+// RUN: llvm-cov show %S/Inputs/showTabsHTML.covmapping -format html -instr-profile %t.profdata -filename-equivalence %s | FileCheck -check-prefix=CHECK %s
+
+int main(int argc, char ** argv) {
+	(void) "This tab starts at column 0";            // CHECK:   (void) "This tab starts at column 0";
+  (void) "	This tab starts at column 10";           // CHECK: (void) "  This tab starts at column 10";
+  (void) "This 	 tab starts at column 15";           // CHECK: (void) "This   tab starts at column 15";
+
+  return 0;
+}
+
+// RUN: llvm-cov show %S/Inputs/showTabsHTML.covmapping -format html -tab-size=3 -instr-profile %t.profdata -filename-equivalence %s | FileCheck -check-prefix=CHECK-TABSIZE %s
+
+// CHECK-TABSIZE:    (void) "This tab starts at column 0";
+// CHECK-TABSIZE: (void) "  This tab starts at column 10";
+// CHECK-TABSIZE: (void) "This     tab starts at column 15";
\ No newline at end of file
Index: tools/llvm-cov/CodeCoverage.cpp
===================================================================
--- tools/llvm-cov/CodeCoverage.cpp
+++ tools/llvm-cov/CodeCoverage.cpp
@@ -584,6 +584,10 @@
   cl::alias ShowOutputDirectoryA("o", cl::desc("Alias for --output-dir"),
                                  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)"));
+
   auto Err = commandLineParser(argc, argv);
   if (Err)
     return Err;
@@ -596,6 +600,7 @@
   ViewOpts.ShowExpandedRegions = ShowExpansions;
   ViewOpts.ShowFunctionInstantiations = ShowInstantiations;
   ViewOpts.ShowOutputDirectory = ShowOutputDirectory;
+  ViewOpts.TabSize = TabSize;
 
   if (ViewOpts.hasOutputDirectory()) {
     if (auto E = sys::fs::create_directories(ViewOpts.ShowOutputDirectory)) {
Index: tools/llvm-cov/CoverageViewOptions.h
===================================================================
--- tools/llvm-cov/CoverageViewOptions.h
+++ tools/llvm-cov/CoverageViewOptions.h
@@ -34,6 +34,7 @@
   OutputFormat Format;
   std::string ShowOutputDirectory;
   std::vector<std::string> DemanglerOpts;
+  uint32_t TabSize;
 
   /// \brief Change the output's stream color if the colors are enabled.
   ColoredRawOstream colored_ostream(raw_ostream &OS,
Index: tools/llvm-cov/SourceCoverageViewHTML.cpp
===================================================================
--- tools/llvm-cov/SourceCoverageViewHTML.cpp
+++ tools/llvm-cov/SourceCoverageViewHTML.cpp
@@ -22,9 +22,11 @@
 namespace {
 
 // Return a string with the special characters in \p Str escaped.
-std::string escape(StringRef Str) {
+std::string escape(StringRef Str, const CoverageViewOptions &Opts) {
   std::string Result;
+  unsigned ColNum = 0; // Record the column number.
   for (char C : Str) {
+    ++ColNum;
     if (C == '&')
       Result += "&amp;";
     else if (C == '<')
@@ -33,7 +35,16 @@
       Result += "&gt;";
     else if (C == '\"')
       Result += "&quot;";
-    else
+    else if (C == '\n' || C == '\r') {
+      Result += C;
+      ColNum = 0;
+    } else if (C == '\t') {
+      // Replace '\t' with TabSize spaces.
+      unsigned NumSpaces = Opts.TabSize - (--ColNum % Opts.TabSize);
+      for (unsigned I = 0; I < NumSpaces; ++I)
+        Result += "&nbsp;";
+      ColNum += NumSpaces;
+    } else
       Result += C;
   }
   return Result;
@@ -195,7 +206,8 @@
   return PathToStyle + "style.css";
 }
 
-void emitPrelude(raw_ostream &OS, const std::string &PathToStyle = "") {
+void emitPrelude(raw_ostream &OS, const CoverageViewOptions &Opts,
+                 const std::string &PathToStyle = "") {
   OS << "<!doctype html>"
         "<html>"
      << BeginHeader;
@@ -204,8 +216,8 @@
   if (PathToStyle.empty())
     OS << "<style>" << CSSForCoverage << "</style>";
   else
-    OS << "<link rel='stylesheet' type='text/css' href='" << escape(PathToStyle)
-       << "'>";
+    OS << "<link rel='stylesheet' type='text/css' href='"
+       << escape(PathToStyle, Opts) << "'>";
 
   OS << EndHeader << "<body>" << BeginCenteredDiv;
 }
@@ -226,10 +238,10 @@
   OwnedStream OS = std::move(OSOrErr.get());
 
   if (!Opts.hasOutputDirectory()) {
-    emitPrelude(*OS.get());
+    emitPrelude(*OS.get(), Opts);
   } else {
     std::string ViewPath = getOutputPath(Path, "html", InToplevel);
-    emitPrelude(*OS.get(), getPathToStyle(ViewPath));
+    emitPrelude(*OS.get(), Opts, getPathToStyle(ViewPath));
   }
 
   return std::move(OS);
@@ -248,13 +260,13 @@
 
   // Emit a table containing links to reports for each file in the covmapping.
   assert(Opts.hasOutputDirectory() && "No output directory for index file");
-  emitPrelude(OSRef, getPathToStyle(""));
+  emitPrelude(OSRef, Opts, getPathToStyle(""));
   OSRef << BeginSourceNameDiv << "Index" << EndSourceNameDiv;
   OSRef << BeginTable;
   for (StringRef SF : SourceFiles) {
-    std::string LinkText = escape(sys::path::relative_path(SF));
+    std::string LinkText = escape(sys::path::relative_path(SF), Opts);
     std::string LinkTarget =
-        escape(getOutputPath(SF, "html", /*InToplevel=*/false));
+        escape(getOutputPath(SF, "html", /*InToplevel=*/false), Opts);
     OSRef << tag("tr", tag("td", tag("pre", a(LinkTarget, LinkText), "code")));
   }
   OSRef << EndTable;
@@ -280,7 +292,7 @@
 }
 
 void SourceCoverageViewHTML::renderSourceName(raw_ostream &OS) {
-  OS << BeginSourceNameDiv << tag("pre", escape(getSourceName()))
+  OS << BeginSourceNameDiv << tag("pre", escape(getSourceName(), getOptions()))
      << EndSourceNameDiv;
 }
 
@@ -336,7 +348,7 @@
   // 2. Escape all of the snippets.
 
   for (unsigned I = 0, E = Snippets.size(); I < E; ++I)
-    Snippets[I] = escape(Snippets[I]);
+    Snippets[I] = escape(Snippets[I], getOptions());
 
   // 3. Use \p WrappedSegment to set the highlight for snippet 0. Use segment
   //    1 to set the highlight for snippet 2, segment 2 to set the highlight for