llvm-cov: add code coverage tool that's based on coverage mapping format and clang's pgo.

This commit expands llvm-cov's functionality by adding support for a new code coverage
tool that uses LLVM's coverage mapping format and clang's instrumentation based profiling.
The gcov compatible tool can be invoked by supplying the 'gcov' command as the first argument,
or by modifying the tool's name to end with 'gcov'.

Differential Revision: http://reviews.llvm.org/D4445


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216300 91177308-0d34-0410-b5e6-96231b3b80d8

tools/llvm-cov/llvm-cov.cpp

@@ -11,9 +11,63 @@
 //
 //===----------------------------------------------------------------------===//
 
-/// \brief The main function for the gcov compatible coverage tool
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/Path.h"
+#include <string>
+
+using namespace llvm;
+
+/// \brief The main entry point for the 'show' subcommand.
+int show_main(int argc, const char **argv);
+
+/// \brief The main entry point for the 'report' subcommand.
+int report_main(int argc, const char **argv);
+
+/// \brief The main entry point for the 'convert-for-testing' subcommand.
+int convert_for_testing_main(int argc, const char **argv);
+
+/// \brief The main entry point for the gcov compatible coverage tool.
 int gcov_main(int argc, const char **argv);
 
 int main(int argc, const char **argv) {
+  // If argv[0] is or ends with 'gcov', always be gcov compatible
+  if (sys::path::stem(argv[0]).endswith_lower("gcov"))
+    return gcov_main(argc, argv);
+
+  // Check if we are invoking a specific tool command.
+  if (argc > 1) {
+    int (*func)(int, const char **) = nullptr;
+
+    StringRef command = argv[1];
+    if (command.equals_lower("show"))
+      func = show_main;
+    else if (command.equals_lower("report"))
+      func = report_main;
+    else if (command.equals_lower("convert-for-testing"))
+      func = convert_for_testing_main;
+    else if (command.equals_lower("gcov"))
+      func = gcov_main;
+
+    if (func) {
+      std::string Invocation(std::string(argv[0]) + " " + argv[1]);
+      argv[1] = Invocation.c_str();
+      return func(argc - 1, argv + 1);
+    }
+  }
+
+  // Give a warning and fall back to gcov
+  errs().changeColor(raw_ostream::RED);
+  errs() << "warning:";
+  // Assume that argv[1] wasn't a command when it stats with a '-' or is a
+  // filename (i.e. contains a '.')
+  if (argc > 1 && !StringRef(argv[1]).startswith("-") &&
+      StringRef(argv[1]).find(".") == StringRef::npos)
+    errs() << " Unrecognized command '" << argv[1] << "'.";
+  errs() << " Using the gcov compatible mode "
+            "(this behaviour may be dropped in the future).";
+  errs().resetColor();
+  errs() << "\n";
+
   return gcov_main(argc, argv);
 }