Add comment describing what's going on here.

llvm-svn: 167525

1 files changed, 21 insertions, 0 deletions

diff --git a/llvm/tools/llvm-cov/llvm-cov.cpp b/llvm/tools/llvm-cov/llvm-cov.cpp
index 7b21c5bae20..ce5ff9c450e 100644
--- a/llvm/tools/llvm-cov/llvm-cov.cpp
+++ b/llvm/tools/llvm-cov/llvm-cov.cpp
@@ -16,11 +16,15 @@
 #include "llvm/Support/GCOV.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/MemoryObject.h"
+#include "llvm/Support/Path.h"
 #include "llvm/Support/PrettyStackTrace.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/system_error.h"
 using namespace llvm;
 
+static cl::opt<std::string>
+InputFilename(cl::Positional, cl::desc("source filename"), cl::init(""));
+
 static cl::opt<bool>
 DumpGCOV("dump", cl::init(false), cl::desc("dump gcov file"));
 
@@ -40,6 +44,23 @@ int main(int argc, char **argv) {
 
   cl::ParseCommandLineOptions(argc, argv, "llvm cov\n");
 
+  if (InputFilename.empty()) {
+    // FIXME: Error out here.
+  }
+
+  sys::Path SrcFile(InputFilename);
+
+  sys::Path GCNOFile(SrcFile);
+  GCNOFile.eraseSuffix();
+  GCNOFile.appendSuffix(".gcno");
+
+  sys::Path GCDAFile(SrcFile);
+  GCDAFile.eraseSuffix();
+  GCDAFile.appendSuffix(".gcda");
+
+  sys::Path OutputFile(SrcFile);
+  OutputFile.appendSuffix(".gcov");
+
   GCOVFile GF;
   if (InputGCNO.empty())
     errs() << " " << argv[0] << ": No gcov input file!\n";