ProfileData: Introduce the InstrProfReader interface and a text reader

This introduces the ProfileData library and updates llvm-profdata to
use this library for reading profiles. InstrProfReader is an abstract
base class that will be subclassed for both the raw instrprof data
from compiler-rt and the efficient instrprof format that will be used
for PGO.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204482 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 171 insertions, 0 deletions

diff --git a/include/llvm/ProfileData/InstrProf.h b/include/llvm/ProfileData/InstrProf.h
new file mode 100644
index 0000000000..21cc170065
--- /dev/null
+++ b/include/llvm/ProfileData/InstrProf.h
@@ -0,0 +1,52 @@
+//=-- InstrProf.h - Instrumented profiling format support ---------*- C++ -*-=//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// Instrumentation-based profiling data is generated by instrumented
+// binaries through library functions in compiler-rt, and read by the clang
+// frontend to feed PGO.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_PROFILEDATA_INSTRPROF_H__
+#define LLVM_PROFILEDATA_INSTRPROF_H__
+
+#include "llvm/Support/system_error.h"
+
+namespace llvm {
+
+const error_category &instrprof_category();
+
+struct instrprof_error {
+  enum ErrorType {
+    success = 0,
+    eof,
+    bad_magic,
+    unsupported_version,
+    too_large,
+    truncated,
+    malformed,
+    unknown_function
+  };
+  ErrorType V;
+
+  instrprof_error(ErrorType V) : V(V) {}
+  operator ErrorType() const { return V; }
+};
+
+inline error_code make_error_code(instrprof_error E) {
+  return error_code(static_cast<int>(E), instrprof_category());
+}
+
+template <> struct is_error_code_enum<instrprof_error> : std::true_type {};
+template <> struct is_error_code_enum<instrprof_error::ErrorType>
+  : std::true_type {};
+
+} // end namespace llvm
+
+#endif // LLVM_PROFILEDATA_INSTRPROF_H__
diff --git a/include/llvm/ProfileData/InstrProfReader.h b/include/llvm/ProfileData/InstrProfReader.h
new file mode 100644
index 0000000000..a45318b0a9
--- /dev/null
+++ b/include/llvm/ProfileData/InstrProfReader.h
@@ -0,0 +1,119 @@
+//=-- InstrProfReader.h - Instrumented profiling readers ----------*- C++ -*-=//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains support for reading profiling data for instrumentation
+// based PGO and coverage.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_PROFILEDATA_INSTRPROF_READER_H__
+#define LLVM_PROFILEDATA_INSTRPROF_READER_H__
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ProfileData/InstrProf.h"
+#include "llvm/Support/LineIterator.h"
+#include "llvm/Support/MemoryBuffer.h"
+
+#include <iterator>
+
+namespace llvm {
+
+class InstrProfReader;
+
+/// Profiling information for a single function.
+struct InstrProfRecord {
+  StringRef Name;
+  uint64_t Hash;
+  ArrayRef<uint64_t> Counts;
+};
+
+/// A file format agnostic iterator over profiling data.
+class InstrProfIterator : public std::iterator<std::input_iterator_tag,
+                                               InstrProfRecord> {
+  InstrProfReader *Reader;
+  InstrProfRecord Record;
+
+  void Increment();
+public:
+  InstrProfIterator() : Reader(nullptr) {}
+  InstrProfIterator(InstrProfReader *Reader) : Reader(Reader) { Increment(); }
+
+  InstrProfIterator &operator++() { Increment(); return *this; }
+  bool operator==(const InstrProfIterator &RHS) { return Reader == RHS.Reader; }
+  bool operator!=(const InstrProfIterator &RHS) { return Reader != RHS.Reader; }
+  InstrProfRecord &operator*() { return Record; }
+  InstrProfRecord *operator->() { return &Record; }
+};
+
+/// Base class and interface for reading profiling data of any known instrprof
+/// format. Provides an iterator over InstrProfRecords.
+class InstrProfReader {
+  error_code LastError;
+public:
+  InstrProfReader() : LastError(instrprof_error::success) {}
+  virtual ~InstrProfReader() {}
+
+  /// Read a single record.
+  virtual error_code readNextRecord(InstrProfRecord &Record) = 0;
+  /// Iterator over profile data.
+  InstrProfIterator begin() { return InstrProfIterator(this); }
+  InstrProfIterator end() { return InstrProfIterator(); }
+
+  /// Set the current error_code and return same.
+  error_code error(error_code EC) {
+    LastError = EC;
+    return EC;
+  }
+  /// Clear the current error code and return a successful one.
+  error_code success() { return error(instrprof_error::success); }
+
+  /// Return true if the reader has finished reading the profile data.
+  bool isEOF() { return LastError == instrprof_error::eof; }
+  /// Return true if the reader encountered an error reading profiling data.
+  bool hasError() { return LastError && !isEOF(); }
+  /// Get the current error code.
+  error_code getError() { return LastError; }
+
+  /// Factory method to create an appropriately typed reader for the given
+  /// instrprof file.
+  static error_code create(std::string Path,
+                           std::unique_ptr<InstrProfReader> &Result);
+};
+
+/// Reader for the simple text based instrprof format.
+///
+/// This format is a simple text format that's suitable for test data. Records
+/// are separated by one or more blank lines, and record fields are separated by
+/// new lines.
+///
+/// Each record consists of a function name, a function hash, a number of
+/// counters, and then each counter value, in that order.
+class TextInstrProfReader : public InstrProfReader {
+private:
+  /// The profile data file contents.
+  std::unique_ptr<MemoryBuffer> DataBuffer;
+  /// Iterator over the profile data.
+  line_iterator Line;
+  /// The current set of counter values.
+  std::vector<uint64_t> Counts;
+
+  TextInstrProfReader(const TextInstrProfReader &) LLVM_DELETED_FUNCTION;
+  TextInstrProfReader &operator=(const TextInstrProfReader &)
+    LLVM_DELETED_FUNCTION;
+public:
+  TextInstrProfReader(std::unique_ptr<MemoryBuffer> &DataBuffer_)
+      : DataBuffer(DataBuffer_.release()), Line(*DataBuffer, '#') {}
+
+  /// Read a single record.
+  error_code readNextRecord(InstrProfRecord &Record) override;
+};
+
+} // end namespace llvm
+
+#endif // LLVM_PROFILEDATA_INSTRPROF_READER_H__