[llvm-bcanalyzer] Refactor and move to libLLVMBitReader

This allows us to use the analyzer from unit tests.

* Refactor the interface to use proper error handling for most functions
  after JF's work.
* Move everything into a BitstreamAnalyzer class.
* Move that to Bitcode/BitcodeAnalyzer.h.

Differential Revision: https://reviews.llvm.org/D64116

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@365286 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Bitcode/BitcodeAnalyzer.h

@@ -0,0 +1,103 @@
+//===- llvm/Bitcode/BitcodeAnalyzer.h - Bitcode analyzer --------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This header defines interfaces to analyze LLVM bitcode files/streams.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_BITCODE_BITCODE_ANALYZER_H
+#define LLVM_BITCODE_BITCODE_ANALYZER_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Bitstream/BitstreamReader.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/raw_ostream.h"
+#include <map>
+#include <vector>
+
+namespace llvm {
+
+/// CurStreamTypeType - A type for CurStreamType
+enum CurStreamTypeType {
+  UnknownBitstream,
+  LLVMIRBitstream,
+  ClangSerializedASTBitstream,
+  ClangSerializedDiagnosticsBitstream,
+};
+
+struct BCDumpOptions {
+  /// The stream.
+  raw_ostream &OS;
+  /// Print per-code histogram.
+  bool Histogram = false;
+  /// Don't emit numeric info in dump if symbolic info is available.
+  bool Symbolic = false;
+  /// Print binary blobs using hex escapes.
+  bool ShowBinaryBlobs = false;
+
+  BCDumpOptions(raw_ostream &OS) : OS(OS) {}
+};
+
+class BitcodeAnalyzer {
+  BitstreamCursor Stream;
+  BitstreamBlockInfo BlockInfo;
+  CurStreamTypeType CurStreamType;
+  Optional<BitstreamCursor> BlockInfoStream;
+  unsigned NumTopBlocks = 0;
+
+  struct PerRecordStats {
+    unsigned NumInstances;
+    unsigned NumAbbrev;
+    uint64_t TotalBits;
+    PerRecordStats() : NumInstances(0), NumAbbrev(0), TotalBits(0) {}
+  };
+
+  struct PerBlockIDStats {
+    /// NumInstances - This the number of times this block ID has been seen.
+    unsigned NumInstances;
+    /// NumBits - The total size in bits of all of these blocks.
+    uint64_t NumBits;
+    /// NumSubBlocks - The total number of blocks these blocks contain.
+    unsigned NumSubBlocks;
+    /// NumAbbrevs - The total number of abbreviations.
+    unsigned NumAbbrevs;
+    /// NumRecords - The total number of records these blocks contain, and the
+    /// number that are abbreviated.
+    unsigned NumRecords, NumAbbreviatedRecords;
+    /// CodeFreq - Keep track of the number of times we see each code.
+    std::vector<PerRecordStats> CodeFreq;
+    PerBlockIDStats()
+        : NumInstances(0), NumBits(0), NumSubBlocks(0), NumAbbrevs(0),
+          NumRecords(0), NumAbbreviatedRecords(0) {}
+  };
+
+  std::map<unsigned, PerBlockIDStats> BlockIDStats;
+
+public:
+  BitcodeAnalyzer(StringRef Buffer, Optional<StringRef> BlockInfoBuffer = None);
+  /// Analyze the bitcode file.
+  Error analyze(Optional<BCDumpOptions> O = None,
+                Optional<StringRef> CheckHash = None);
+  /// Print stats about the bitcode file.
+  void printStats(BCDumpOptions O, Optional<StringRef> Filename = None);
+
+private:
+  /// Read a block, updating statistics, etc.
+  Error parseBlock(unsigned BlockID, unsigned IndentLevel,
+                   Optional<BCDumpOptions> O = None,
+                   Optional<StringRef> CheckHash = None);
+
+  Error decodeMetadataStringsBlob(StringRef Indent, ArrayRef<uint64_t> Record,
+                                  StringRef Blob, raw_ostream &OS);
+};
+
+} // end namespace llvm
+
+#endif // LLVM_BITCODE_BITCODE_ANALYZER_H