llvm-cov: Sink some reporting logic into CoverageMapping

This teaches CoverageMapping::getCoveredFunctions to filter to a
particular file and uses that to replace most of the logic found in
llvm-cov report.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@221962 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/ProfileData/CoverageMapping.h

@@ -18,6 +18,7 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/Hashing.h"
+#include "llvm/ADT/iterator.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/raw_ostream.h"
 #include <system_error>
@@ -240,6 +241,40 @@ struct FunctionRecord {
         ExecutionCount(ExecutionCount) {}
 };
 
+/// \brief Iterator over Functions, optionally filtered to a single file.
+class FunctionRecordIterator
+    : public iterator_facade_base<FunctionRecordIterator,
+                                  std::forward_iterator_tag, FunctionRecord> {
+  ArrayRef<FunctionRecord> Records;
+  ArrayRef<FunctionRecord>::iterator Current;
+  StringRef Filename;
+
+  /// \brief Skip records whose primary file is not \c Filename.
+  void skipOtherFiles();
+
+public:
+  FunctionRecordIterator(ArrayRef<FunctionRecord> Records_,
+                         StringRef Filename = "")
+      : Records(Records_), Current(Records.begin()), Filename(Filename) {
+    skipOtherFiles();
+  }
+
+  FunctionRecordIterator() : Current(Records.begin()) {}
+
+  bool operator==(const FunctionRecordIterator &RHS) const {
+    return Current == RHS.Current && Filename == RHS.Filename;
+  }
+
+  const FunctionRecord &operator*() const { return *Current; }
+
+  FunctionRecordIterator &operator++() {
+    assert(Current != Records.end() && "incremented past end");
+    ++Current;
+    skipOtherFiles();
+    return *this;
+  }
+};
+
 /// \brief Coverage information for a macro expansion or #included file.
 ///
 /// When covered code has pieces that can be expanded for more detail, such as a
@@ -342,7 +377,7 @@ public:
   unsigned getMismatchedCount() { return MismatchedFunctionCount; }
 
   /// \brief Returns the list of files that are covered.
-  std::vector<StringRef> getUniqueSourceFiles();
+  std::vector<StringRef> getUniqueSourceFiles() const;
 
   /// \brief Get the coverage for a particular file.
   ///
@@ -352,8 +387,16 @@ public:
   CoverageData getCoverageForFile(StringRef Filename);
 
   /// \brief Gets all of the functions covered by this profile.
-  ArrayRef<FunctionRecord> getCoveredFunctions() {
-    return ArrayRef<FunctionRecord>(Functions.data(), Functions.size());
+  iterator_range<FunctionRecordIterator> getCoveredFunctions() const {
+    return make_range(FunctionRecordIterator(Functions),
+                      FunctionRecordIterator());
+  }
+
+  /// \brief Gets all of the functions in a particular file.
+  iterator_range<FunctionRecordIterator>
+  getCoveredFunctions(StringRef Filename) const {
+    return make_range(FunctionRecordIterator(Functions, Filename),
+                      FunctionRecordIterator());
   }
 
   /// \brief Get the list of function instantiations in the file.