Index: tools/llvm-cov/CodeCoverage.cpp
===================================================================
--- tools/llvm-cov/CodeCoverage.cpp
+++ tools/llvm-cov/CodeCoverage.cpp
@@ -310,6 +310,11 @@
       "use-color", cl::desc("Emit colored output (default=autodetect)"),
       cl::init(cl::BOU_UNSET));
 
+  cl::opt<bool> ShowFullFilenames(
+      "full-filenames", cl::Optional,
+      cl::desc("Show full filenames in the coverage report (default=false)"),
+      cl::init(false));
+
   auto commandLineParser = [&, this](int argc, const char **argv) -> int {
     cl::ParseCommandLineOptions(argc, argv, "LLVM code coverage tool\n");
     ViewOpts.Debug = DebugDump;
@@ -318,6 +323,7 @@
     ViewOpts.Colors = UseColor == cl::BOU_UNSET
                           ? sys::Process::StandardOutHasColors()
                           : UseColor == cl::BOU_TRUE;
+    ViewOpts.ShowFullFilenames = ShowFullFilenames;
 
     // Create the function filters
     if (!NameFilters.empty() || !NameRegexFilters.empty()) {
Index: tools/llvm-cov/CoverageReport.cpp
===================================================================
--- tools/llvm-cov/CoverageReport.cpp
+++ tools/llvm-cov/CoverageReport.cpp
@@ -20,7 +20,7 @@
 namespace {
 /// \brief Helper struct which prints trimmed and aligned columns.
 struct Column {
-  enum TrimKind { NoTrim, LeftTrim, RightTrim };
+  enum TrimKind { NoTrim, WidthTrim, LeftTrim, RightTrim };
 
   enum AlignmentKind { LeftAlignment, RightAlignment };
 
@@ -30,7 +30,7 @@
   AlignmentKind Alignment;
 
   Column(StringRef Str, unsigned Width)
-      : Str(Str), Width(Width), Trim(NoTrim), Alignment(LeftAlignment) {}
+      : Str(Str), Width(Width), Trim(WidthTrim), Alignment(LeftAlignment) {}
 
   Column &set(TrimKind Value) {
     Trim = Value;
@@ -44,6 +44,7 @@
 
   void render(raw_ostream &OS) const;
 };
+
 raw_ostream &operator<<(raw_ostream &OS, const Column &Value) {
   Value.render(OS);
   return OS;
@@ -64,6 +65,9 @@
 
   switch (Trim) {
   case NoTrim:
+    OS << Str;
+    break;
+  case WidthTrim:
     OS << Str.substr(0, Width);
     break;
   case LeftTrim:
@@ -84,8 +88,8 @@
   return Column(Str, Width).set(Value);
 }
 
-static const unsigned FileReportColumns[] = {25, 10, 8, 8, 10, 10};
-static const unsigned FunctionReportColumns[] = {25, 10, 8, 8, 10, 8, 8};
+static size_t FileReportColumns[] = {25, 10, 8, 8, 10, 10};
+static size_t FunctionReportColumns[] = {25, 10, 8, 8, 10, 8, 8};
 
 /// \brief Prints a horizontal divider which spans across the given columns.
 template <typename T, size_t N>
@@ -108,8 +112,10 @@
 }
 
 void CoverageReport::render(const FileCoverageSummary &File, raw_ostream &OS) {
-  OS << column(File.Name, FileReportColumns[0], Column::LeftTrim)
-     << format("%*u", FileReportColumns[1], (unsigned)File.RegionCoverage.NumRegions);
+  OS << column(File.Name, FileReportColumns[0],
+               Options.ShowFullFilenames ? Column::NoTrim : Column::LeftTrim)
+     << format("%*u", FileReportColumns[1],
+               (unsigned)File.RegionCoverage.NumRegions);
   Options.colored_ostream(OS, File.RegionCoverage.isFullyCovered()
                                   ? raw_ostream::GREEN
                                   : raw_ostream::RED)
@@ -191,6 +197,11 @@
 }
 
 void CoverageReport::renderFileReports(raw_ostream &OS) {
+  if (Options.ShowFullFilenames) {
+    for (StringRef Filename : Coverage->getUniqueSourceFiles()) {
+      FileReportColumns[0] = std::max(FileReportColumns[0], Filename.size());
+    }
+  }
   OS << column("Filename", FileReportColumns[0])
      << column("Regions", FileReportColumns[1], Column::RightAlignment)
      << column("Miss", FileReportColumns[2], Column::RightAlignment)
Index: tools/llvm-cov/CoverageViewOptions.h
===================================================================
--- tools/llvm-cov/CoverageViewOptions.h
+++ tools/llvm-cov/CoverageViewOptions.h
@@ -24,6 +24,7 @@
   bool ShowLineStatsOrRegionMarkers;
   bool ShowExpandedRegions;
   bool ShowFunctionInstantiations;
+  bool ShowFullFilenames;
 
   /// \brief Change the output's stream color if the colors are enabled.
   ColoredRawOstream colored_ostream(raw_ostream &OS,