InstrProf: Make CoverageMapping testable and add a basic unit test

Make CoverageMapping easier to create, so that we can write targeted
unit tests for its internals, and add a some infrastructure to write
these tests. Finally, add a simple unit test for basic functionality.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@229709 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ProfileData/CoverageMapping.h

@@ -28,7 +28,7 @@ namespace llvm {
 class IndexedInstrProfReader;
 namespace coverage {
 
-class ObjectFileCoverageMappingReader;
+class CoverageMappingReader;
 
 class CoverageMapping;
 struct CounterExpressions;
@@ -333,10 +333,22 @@ struct CoverageSegment {
   CoverageSegment(unsigned Line, unsigned Col, bool IsRegionEntry)
       : Line(Line), Col(Col), Count(0), HasCount(false),
         IsRegionEntry(IsRegionEntry) {}
+
+  CoverageSegment(unsigned Line, unsigned Col, uint64_t Count,
+                  bool IsRegionEntry)
+      : Line(Line), Col(Col), Count(Count), HasCount(true),
+        IsRegionEntry(IsRegionEntry) {}
+
+  friend bool operator==(const CoverageSegment &L, const CoverageSegment &R) {
+    return std::tie(L.Line, L.Col, L.Count, L.HasCount, L.IsRegionEntry) ==
+           std::tie(R.Line, R.Col, R.Count, R.HasCount, R.IsRegionEntry);
+  }
+
   void setCount(uint64_t NewCount) {
     Count = NewCount;
     HasCount = true;
   }
+
   void addCount(uint64_t NewCount) { setCount(Count + NewCount); }
 };
 
@@ -384,7 +396,7 @@ class CoverageMapping {
 public:
   /// \brief Load the coverage mapping using the given readers.
   static ErrorOr<std::unique_ptr<CoverageMapping>>
-  load(ObjectFileCoverageMappingReader &CoverageReader,
+  load(CoverageMappingReader &CoverageReader,
        IndexedInstrProfReader &ProfileReader);
 
   /// \brief Load the coverage mapping from the given files.

include/llvm/ProfileData/CoverageMappingReader.h

@@ -27,7 +27,7 @@
 namespace llvm {
 namespace coverage {
 
-class ObjectFileCoverageMappingReader;
+class CoverageMappingReader;
 
 /// \brief Coverage mapping information for a single function.
 struct CoverageMappingRecord {
@@ -41,15 +41,14 @@ struct CoverageMappingRecord {
 /// \brief A file format agnostic iterator over coverage mapping data.
 class CoverageMappingIterator
     : public std::iterator<std::input_iterator_tag, CoverageMappingRecord> {
-  ObjectFileCoverageMappingReader *Reader;
+  CoverageMappingReader *Reader;
   CoverageMappingRecord Record;
 
   void increment();
 
 public:
   CoverageMappingIterator() : Reader(nullptr) {}
-  CoverageMappingIterator(ObjectFileCoverageMappingReader *Reader)
-      : Reader(Reader) {
+  CoverageMappingIterator(CoverageMappingReader *Reader) : Reader(Reader) {
     increment();
   }
 
@@ -67,6 +66,14 @@ public:
   CoverageMappingRecord *operator->() { return &Record; }
 };
 
+class CoverageMappingReader {
+public:
+  virtual std::error_code readNextRecord(CoverageMappingRecord &Record) = 0;
+  CoverageMappingIterator begin() { return CoverageMappingIterator(this); }
+  CoverageMappingIterator end() { return CoverageMappingIterator(); }
+  virtual ~CoverageMappingReader() {}
+};
+
 /// \brief Base class for the raw coverage mapping and filenames data readers.
 class RawCoverageReader {
 protected:
@@ -135,7 +142,7 @@ private:
 
 /// \brief Reader for the coverage mapping data that is emitted by the
 /// frontend and stored in an object file.
-class ObjectFileCoverageMappingReader {
+class ObjectFileCoverageMappingReader : public CoverageMappingReader {
 public:
   struct ProfileMappingRecord {
     CoverageMappingVersion Version;
@@ -184,11 +191,7 @@ public:
       sys::fs::file_magic Type = sys::fs::file_magic::unknown);
 
   std::error_code readHeader();
-  std::error_code readNextRecord(CoverageMappingRecord &Record);
-
-  /// Iterator over profile data.
-  CoverageMappingIterator begin() { return CoverageMappingIterator(this); }
-  CoverageMappingIterator end() { return CoverageMappingIterator(); }
+  std::error_code readNextRecord(CoverageMappingRecord &Record) override;
 
   /// \brief Return true if the reader has finished reading the profile data.
   bool isEOF() { return LastError == instrprof_error::eof; }