Index: test/tools/llvm-cov/Inputs/cov_dir/main.cpp
===================================================================
--- test/tools/llvm-cov/Inputs/cov_dir/main.cpp
+++ test/tools/llvm-cov/Inputs/cov_dir/main.cpp
@@ -0,0 +1,12 @@
+#include <stdio.h>
+
+extern int f(int g);
+int main(int argc, char **argv) {
+  int result = 0;
+  int a;
+  scanf("%d", &a);
+  result = f(a);
+  return result;
+  result = 10;
+  return 0;
+}
Index: test/tools/llvm-cov/Inputs/cov_dir/sub_dir/function.cpp
===================================================================
--- test/tools/llvm-cov/Inputs/cov_dir/sub_dir/function.cpp
+++ test/tools/llvm-cov/Inputs/cov_dir/sub_dir/function.cpp
@@ -0,0 +1,5 @@
+int f(int g) {
+  return g + 2;
+  g += 4;
+  return g;
+}
Index: test/tools/llvm-cov/cov_dir.cpp
===================================================================
--- test/tools/llvm-cov/cov_dir.cpp
+++ test/tools/llvm-cov/cov_dir.cpp
@@ -0,0 +1,13 @@
+// RUN: llvm-cov report %S/Inputs/cov_dir.covmapping -instr-profile %S/Inputs/cov_dir.profdata -filename-equivalence main.cpp function.cpp 2>&1 | FileCheck %s
+
+// CHECK:      Name                        Regions    Miss   Cover     Lines    Miss   Cover
+// CHECK-NEXT: ---
+// CHECK-NEXT: main                              2       1  50.00%         8       2  75.00%
+// CHECK-NEXT: ---
+// CHECK-NEXT: TOTAL                             2       1  50.00%         8       2  75.00%
+
+// CHECK:      Name                        Regions    Miss   Cover     Lines    Miss   Cover
+// CHECK-NEXT: ---
+// CHECK-NEXT: _Z1fi                             2       1  50.00%         5       2  60.00%
+// CHECK-NEXT: ---
+// CHECK-NEXT: TOTAL                             2       1  50.00%         5       2  60.00%
Index: tools/llvm-cov/CodeCoverage.cpp
===================================================================
--- tools/llvm-cov/CodeCoverage.cpp
+++ tools/llvm-cov/CodeCoverage.cpp
@@ -70,6 +70,9 @@
   /// \brief Load the coverage mapping data. Return true if an error occured.
   std::unique_ptr<CoverageMapping> load();
 
+  /// \brief Collects all source files recursively inside the directory
+  void collectSourceFiles(StringRef Path);
+
   int run(Command Cmd, int argc, const char **argv);
 
   typedef std::function<int(int, const char **)> CommandLineParserType;
@@ -239,6 +242,36 @@
   return Coverage;
 }
 
+void CodeCoverageTool::collectSourceFiles(StringRef Path) {
+  if (CompareFilenamesOnly) {
+    SourceFiles.push_back(Path.str());
+    return;
+  }
+  llvm::sys::fs::file_status Status;
+  llvm::sys::fs::status(Path, Status);
+  if (llvm::sys::fs::exists(Status)) {
+    // If it's a source file, collect it.
+    if (llvm::sys::fs::is_regular_file(Status)) {
+      SourceFiles.push_back(Path.str());
+      return;
+    }
+    if (llvm::sys::fs::is_directory(Status)) {
+      std::error_code EC;
+      // Collect all source files within this directory by iterating
+      // recursively.
+      for (llvm::sys::fs::recursive_directory_iterator File(Path, EC), FileEnd;
+           File != FileEnd && !EC; File.increment(EC)) {
+        if (llvm::sys::fs::is_regular_file(File->path())) {
+          SourceFiles.push_back(File->path());
+        }
+      }
+      return;
+    }
+  } else
+    fprintf(stderr, "Error: Can't access: %s\n", Path.str().c_str());
+  return;
+}
+
 int CodeCoverageTool::run(Command Cmd, int argc, const char **argv) {
   // Print a stack trace if we signal out.
   sys::PrintStackTraceOnErrorSignal();
@@ -362,7 +395,7 @@
           errs() << "error: " << File << ": " << EC.message();
           return 1;
         }
-      SourceFiles.push_back(Path.str());
+      collectSourceFiles(Path.str());
     }
     return 0;
   };