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

llvm-svn: 216300

1 files changed, 92 insertions, 0 deletions

diff --git a/llvm/tools/llvm-cov/TestingSupport.cpp b/llvm/tools/llvm-cov/TestingSupport.cpp
new file mode 100644
index 00000000000..8f580cf64f8
--- /dev/null
+++ b/llvm/tools/llvm-cov/TestingSupport.cpp
@@ -0,0 +1,92 @@
+//===- TestingSupport.cpp - Convert objects files into test files --------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Object/ObjectFile.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/LEB128.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/MemoryObject.h"
+#include "llvm/Support/Signals.h"
+#include "llvm/Support/PrettyStackTrace.h"
+#include <system_error>
+#include <functional>
+
+using namespace llvm;
+using namespace object;
+
+int convert_for_testing_main(int argc, const char **argv) {
+  sys::PrintStackTraceOnErrorSignal();
+  PrettyStackTraceProgram X(argc, argv);
+  llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
+
+  cl::opt<std::string> InputSourceFile(cl::Positional, cl::Required,
+                                       cl::desc("<Source file>"));
+
+  cl::opt<std::string> OutputFilename(
+      "o", cl::Required,
+      cl::desc(
+          "File with the profile data obtained after an instrumented run"));
+
+  cl::ParseCommandLineOptions(argc, argv, "LLVM code coverage tool\n");
+
+  auto ObjErr = llvm::object::ObjectFile::createObjectFile(InputSourceFile);
+  if (auto Err = ObjErr.getError()) {
+    errs() << "error: " << Err.message() << "\n";
+    return 1;
+  }
+  ObjectFile *OF = ObjErr.get().getBinary().get();
+  auto BytesInAddress = OF->getBytesInAddress();
+  if (BytesInAddress != 8) {
+    errs() << "error: 64 bit binary expected\n";
+    return 1;
+  }
+
+  // Look for the sections that we are interested in.
+  int FoundSectionCount = 0;
+  SectionRef ProfileNames, CoverageMapping;
+  for (const auto &Section : OF->sections()) {
+    StringRef Name;
+    if (Section.getName(Name))
+      return 1;
+    if (Name == "__llvm_prf_names") {
+      ProfileNames = Section;
+    } else if (Name == "__llvm_covmap") {
+      CoverageMapping = Section;
+    } else
+      continue;
+    ++FoundSectionCount;
+  }
+  if (FoundSectionCount != 2)
+    return 1;
+
+  // Get the contents of the given sections.
+  StringRef CoverageMappingData;
+  uint64_t ProfileNamesAddress;
+  StringRef ProfileNamesData;
+  if (CoverageMapping.getContents(CoverageMappingData) ||
+      ProfileNames.getAddress(ProfileNamesAddress) ||
+      ProfileNames.getContents(ProfileNamesData))
+    return 1;
+
+  int FD;
+  if (auto Err =
+          sys::fs::openFileForWrite(OutputFilename, FD, sys::fs::F_None)) {
+    errs() << "error: " << Err.message() << "\n";
+    return 1;
+  }
+
+  raw_fd_ostream OS(FD, true);
+  OS << "llvmcovmtestdata";
+  encodeULEB128(ProfileNamesData.size(), OS);
+  encodeULEB128(ProfileNamesAddress, OS);
+  OS << ProfileNamesData << CoverageMappingData;
+
+  return 0;
+}