Rebased PNaCl localmods in LLVM to 223109

include/llvm/Bitcode/NaCl/NaClBitCodes.h

+//===- NaClBitCodes.h - Enum values for the bitcode format ------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This header Bitcode enum values.
+//
+// The enum values defined in this file should be considered permanent.  If
+// new features are added, they should have values added at the end of the
+// respective lists.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_BITCODE_NACL_NACLBITCODES_H
+#define LLVM_BITCODE_NACL_NACLBITCODES_H
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/ErrorHandling.h"
+#include "llvm/Support/MathExtras.h"
+#include <cassert>
+
+namespace llvm {
+class raw_ostream;
+
+namespace naclbitc {
+  enum StandardWidths {
+    BlockIDWidth   = 8,  // We use VBR-8 for block IDs.
+    CodeLenWidth   = 4,  // Codelen are VBR-4.
+    BlockSizeWidth = 32, // BlockSize up to 2^32 32-bit words = 16GB per block.
+    MaxAbbrevWidth = 32  // Maximum value allowed for Fixed and VBR.
+  };
+
+  // The standard abbrev namespace always has a way to exit a block, enter a
+  // nested block, define abbrevs, and define an unabbreviated record.
+  enum FixedAbbrevIDs {
+    END_BLOCK = 0,  // Must be zero to guarantee termination for broken bitcode.
+    ENTER_SUBBLOCK = 1,
+
+    /// DEFINE_ABBREV - Defines an abbrev for the current block.  It consists
+    /// of a vbr5 for # operand infos.  Each operand info is emitted with a
+    /// single bit to indicate if it is a literal encoding.  If so, the value is
+    /// emitted with a vbr8.  If not, the encoding is emitted as 3 bits followed
+    /// by the info value as a vbr5 if needed.
+    DEFINE_ABBREV = 2,
+
+    // UNABBREV_RECORDs are emitted with a vbr6 for the record code, followed by
+    // a vbr6 for the # operands, followed by vbr6's for each operand.
+    UNABBREV_RECORD = 3,
+
+    // This is not a code, this is a marker for the first abbrev assignment.
+    // In addition, we assume up to two additional enumerated constants are
+    // added for each extension. These constants are:
+    //
+    //   PREFIX_MAX_FIXED_ABBREV
+    //   PREFIX_MAX_ABBREV
+    //
+    // PREFIX_MAX_ABBREV defines the maximal enumeration value used for
+    // the code selector of a block. If Both PREFIX_MAX_FIXED_ABBREV
+    // and PREFIX_MAX_ABBREV is defined, then PREFIX_MAX_FIXED_ABBREV
+    // defines the last code selector of the block that must be read using
+    // a single read (i.e. a FIXED read, or the first chunk of a VBR read.
+    FIRST_APPLICATION_ABBREV = 4,
+    // Defines default values for code length, if no additional selectors
+    // are added.
+    DEFAULT_MAX_ABBREV = FIRST_APPLICATION_ABBREV-1
+  };
+
+  /// StandardBlockIDs - All bitcode files can optionally include a BLOCKINFO
+  /// block, which contains metadata about other blocks in the file.
+  enum StandardBlockIDs {
+    /// BLOCKINFO_BLOCK is used to define metadata about blocks, for example,
+    /// standard abbrevs that should be available to all blocks of a specified
+    /// ID.
+    BLOCKINFO_BLOCK_ID = 0,
+
+    // Block IDs 1-7 are reserved for future expansion.
+    FIRST_APPLICATION_BLOCKID = 8
+  };
+
+  /// BlockInfoCodes - The blockinfo block contains metadata about user-defined
+  /// blocks.
+  enum BlockInfoCodes {
+    // DEFINE_ABBREV has magic semantics here, applying to the current SETBID'd
+    // block, instead of the BlockInfo block.
+
+    BLOCKINFO_CODE_SETBID        = 1, // SETBID: [blockid#]
+                                      // The following two codes were removed
+                                      // because the PNaCl reader could read
+                                      // them, but couldn't be generated by
+                                      // the writer.
+    BLOCKINFO_CODE_BLOCKNAME     = 2, // Not used in PNaCl.
+    BLOCKINFO_CODE_SETRECORDNAME = 3  // Not used in PNaCl.
+  };
+
+} // End naclbitc namespace
+
+/// NaClBitCodeAbbrevOp - This describes one or more operands in an abbreviation.
+/// This is actually a union of two different things:
+///   1. It could be a literal integer value ("the operand is always 17").
+///   2. It could be an encoding specification ("this operand encoded like so").
+///
+class NaClBitCodeAbbrevOp {
+public:
+  enum Encoding {
+    Literal = 0, // Value is literal value.
+    Fixed = 1,   // A fixed width field, Val specifies number of bits.
+    VBR   = 2,   // A VBR field where Val specifies the width of each chunk.
+    Array = 3,   // A sequence of fields, next field species elt encoding.
+    Char6 = 4,   // A 6-bit fixed field which maps to [a-zA-Z0-9._].
+    Encoding_MAX = Char6
+  };
+
+  explicit NaClBitCodeAbbrevOp(uint64_t V) :  Enc(Literal), Val(V) {}
+  explicit NaClBitCodeAbbrevOp(Encoding E, uint64_t Data = 0);
+
+  Encoding getEncoding() const { return Enc; }
+
+  static bool isValidEncoding(uint64_t Enc) { return Enc <= Encoding_MAX; }
+
+  uint64_t getValue() const { return Val; }
+
+  bool hasValue() const {
+    return hasValue(Enc);
+  }
+  static bool hasValue(Encoding E) {
+    return E <= Encoding_MAX && HasValueArray[E];
+  }
+
+  bool isValid() const { return isValid(Enc, Val); }
+  static bool isValid(Encoding E, uint64_t Val);
+  static bool isValid(Encoding E) { return isValid(E, 0); }
+
+  bool isLiteral() const { return Enc == Literal; }
+
+  bool isArrayOp() const { return Enc == Array; }
+
+  /// Returns the number of arguments expected by this abbrevation operator.
+  unsigned NumArguments() const {
+    if (isArrayOp())
+      return 1;
+    else
+      return 0;
+  }
+
+  // Returns the name of the encoding
+  static const char *getEncodingName(Encoding E) {
+    if (E > Encoding_MAX)
+      return "???";
+    return EncodingNameArray[E];
+  }
+
+  /// Prints out the abbreviation operator to the given stream.
+  void Print(raw_ostream &Stream) const;
+
+  /// isChar6 - Return true if this character is legal in the Char6 encoding.
+  static bool isChar6(char C) {
+    if (C >= 'a' && C <= 'z') return true;
+    if (C >= 'A' && C <= 'Z') return true;
+    if (C >= '0' && C <= '9') return true;
+    if (C == '.' || C == '_') return true;
+    return false;
+  }
+  static unsigned EncodeChar6(char C) {
+    if (C >= 'a' && C <= 'z') return C-'a';
+    if (C >= 'A' && C <= 'Z') return C-'A'+26;
+    if (C >= '0' && C <= '9') return C-'0'+26+26;
+    if (C == '.')             return 62;
+    if (C == '_')             return 63;
+    llvm_unreachable("Not a value Char6 character!");
+  }
+
+  static char DecodeChar6(unsigned V) {
+    assert((V & ~63) == 0 && "Not a Char6 encoded character!");
+    if (V < 26)       return V+'a';
+    if (V < 26+26)    return V-26+'A';
+    if (V < 26+26+10) return V-26-26+'0';
+    if (V == 62)      return '.';
+    if (V == 63)      return '_';
+    llvm_unreachable("Not a value Char6 character!");
+  }
+
+  /// \brief Compares this to Op. Returns <0 if this is less than Op,
+  /// Returns 0 if they are equal, and >0 if this is greater than Op.
+  int Compare(const NaClBitCodeAbbrevOp &Op) const {
+    // Compare encoding values.
+    int EncodingDiff = static_cast<int>(Enc) - static_cast<int>(Op.Enc);
+    if (EncodingDiff != 0) return EncodingDiff;
+
+    // Encodings don't differ, so now base on data associated with the
+    // encoding.
+    return ValCompare(Op);
+  }
+
+private:
+  Encoding Enc;           // The encoding to use.
+  uint64_t Val;           // Data associated with encoding (if any).
+
+  int ValCompare(const NaClBitCodeAbbrevOp &Op) const {
+    if (Val < Op.Val)
+      return -1;
+    else if (Val > Op.Val)
+      return 1;
+    else
+      return 0;
+  }
+  static const bool HasValueArray[];
+  static const char *EncodingNameArray[];
+};
+
+template <> struct isPodLike<NaClBitCodeAbbrevOp> {
+  static const bool value=true;
+};
+
+static inline bool operator<(const NaClBitCodeAbbrevOp &Op1,
+                             const NaClBitCodeAbbrevOp &Op2) {
+  return Op1.Compare(Op2) < 0;
+}
+
+static inline bool operator<=(const NaClBitCodeAbbrevOp &Op1,
+                              const NaClBitCodeAbbrevOp &Op2) {
+  return Op1.Compare(Op2) <= 0;
+}
+
+static inline bool operator==(const NaClBitCodeAbbrevOp &Op1,
+                              const NaClBitCodeAbbrevOp &Op2) {
+  return Op1.Compare(Op2) == 0;
+}
+
+static inline bool operator!=(const NaClBitCodeAbbrevOp &Op1,
+                              const NaClBitCodeAbbrevOp &Op2) {
+  return Op1.Compare(Op2) != 0;
+}
+
+static inline bool operator>=(const NaClBitCodeAbbrevOp &Op1,
+                              const NaClBitCodeAbbrevOp &Op2) {
+  return Op1.Compare(Op2) >= 0;
+}
+
+static inline bool operator>(const NaClBitCodeAbbrevOp &Op1,
+                             const NaClBitCodeAbbrevOp &Op2) {
+  return Op1.Compare(Op2) > 0;
+}
+
+/// NaClBitCodeAbbrev - This class represents an abbreviation record.  An
+/// abbreviation allows a complex record that has redundancy to be stored in a
+/// specialized format instead of the fully-general, fully-vbr, format.
+class NaClBitCodeAbbrev {
+  SmallVector<NaClBitCodeAbbrevOp, 8> OperandList;
+  unsigned char RefCount; // Number of things using this.
+  ~NaClBitCodeAbbrev() {}
+public:
+  NaClBitCodeAbbrev() : RefCount(1) {}
+
+  void addRef() { ++RefCount; }
+  void dropRef() { if (--RefCount == 0) delete this; }
+
+  unsigned getNumOperandInfos() const {
+    return static_cast<unsigned>(OperandList.size());
+  }
+  const NaClBitCodeAbbrevOp &getOperandInfo(unsigned N) const {
+    return OperandList[N];
+  }
+
+  void Add(const NaClBitCodeAbbrevOp &OpInfo) {
+    OperandList.push_back(OpInfo);
+  }
+
+  // Returns a simplified version of the abbreviation. Used
+  // to recognize equivalent abbrevations.
+  NaClBitCodeAbbrev *Simplify() const;
+
+  // Returns true if the abbreviation is valid wrt to the bitcode reader.
+  bool isValid() const;
+
+  int Compare(const NaClBitCodeAbbrev &Abbrev) const {
+    // First order based on number of operands.
+    size_t OperandListSize = OperandList.size();
+    size_t AbbrevOperandListSize = Abbrev.OperandList.size();
+    if (OperandListSize < AbbrevOperandListSize)
+      return -1;
+    else if (OperandListSize > AbbrevOperandListSize)
+      return 1;
+
+    // Same number of operands, so compare element by element.
+    for (size_t I = 0; I < OperandListSize; ++I) {
+      if (int Diff = OperandList[I].Compare(Abbrev.OperandList[I]))
+        return Diff;
+    }
+    return 0;
+  }
+
+  // Returns true if all records matching the abbreviation must be
+  // of fixed length.
+  bool IsFixedSize() const {
+    unsigned Size = getNumOperandInfos();
+    if (Size < 2) return true;
+    return !OperandList[Size-2].isArrayOp();
+  }
+
+  // Returns the smallest record size that will match this
+  // abbreviation.
+  size_t GetMinRecordSize() const {
+    size_t Min = getNumOperandInfos();
+    if (!IsFixedSize()) Min -= 2;
+    return Min;
+  }
+
+  void Print(raw_ostream &Stream, bool AddNewline=true) const;
+
+  NaClBitCodeAbbrev *Copy() const {
+    NaClBitCodeAbbrev *AbbrevCopy = new NaClBitCodeAbbrev();
+    for (unsigned I = 0, IEnd = getNumOperandInfos();
+         I != IEnd; ++I) {
+      AbbrevCopy->Add(NaClBitCodeAbbrevOp(getOperandInfo(I)));
+    }
+    return AbbrevCopy;
+  }
+};
+
+static inline bool operator<(const NaClBitCodeAbbrev &A1,
+                             const NaClBitCodeAbbrev &A2) {
+  return A1.Compare(A2) < 0;
+}
+
+static inline bool operator<=(const NaClBitCodeAbbrev &A1,
+                              const NaClBitCodeAbbrev &A2) {
+  return A1.Compare(A2) <= 0;
+}
+static inline bool operator==(const NaClBitCodeAbbrev &A1,
+                              const NaClBitCodeAbbrev &A2) {
+  return A1.Compare(A2) == 0;
+}
+
+static inline bool operator!=(const NaClBitCodeAbbrev &A1,
+                              const NaClBitCodeAbbrev &A2) {
+  return A1.Compare(A2) != 0;
+}
+static inline bool operator>=(const NaClBitCodeAbbrev &A1,
+                              const NaClBitCodeAbbrev &A2) {
+  return A1.Compare(A2) >= 0;
+}
+
+static inline bool operator>(const NaClBitCodeAbbrev &A1,
+                             const NaClBitCodeAbbrev &A2) {
+  return A1.Compare(A2) > 0;
+}
+
+/// \brief Returns number of bits needed to encode
+/// value for dense FIXED encoding.
+inline unsigned NaClBitsNeededForValue(unsigned Value) {
+  // Note: Need to handle case where Value=0xFFFFFFFF as special case,
+  // since we can't add 1 to it.
+  if (Value >= 0x80000000) return 32;
+  return Log2_32_Ceil(Value+1);
+}
+
+/// \brief Encode a signed value by moving the sign to the LSB for dense
+/// VBR encoding.
+inline uint64_t NaClEncodeSignRotatedValue(int64_t V) {
+  return (V >= 0) ? (V << 1) : ((-V << 1) | 1);
+}
+
+/// \brief Decode a signed value stored with the sign bit in
+/// the LSB for dense VBR encoding.
+inline uint64_t NaClDecodeSignRotatedValue(uint64_t V) {
+  if ((V & 1) == 0)
+    return V >> 1;
+  if (V != 1)
+    return -(V >> 1);
+  // There is no such thing as -0 with integers.  "-0" really means MININT.
+  return 1ULL << 63;
+}
+
+/// \brief This class determines whether a FIXED or VBR
+/// abbreviation should be used for the selector, and the number of bits
+/// needed to capture such selectors.
+class NaClBitcodeSelectorAbbrev {
+
+public:
+  // If true, use a FIXED abbreviation. Otherwise, use a VBR abbreviation.
+  bool IsFixed;
+  // Number of bits needed for selector.
+  unsigned NumBits;
+
+  // Creates a selector range for the given values.
+  NaClBitcodeSelectorAbbrev(bool IF, unsigned NB)
+      : IsFixed(IF), NumBits(NB) {}
+
+  // Creates a selector range when no abbreviations are defined.
+  NaClBitcodeSelectorAbbrev()
+      : IsFixed(true),
+        NumBits(NaClBitsNeededForValue(naclbitc::DEFAULT_MAX_ABBREV)) {}
+
+  // Creates a selector range to handle fixed abbrevations up to
+  // the specified value.
+  explicit NaClBitcodeSelectorAbbrev(unsigned MaxAbbrev)
+      : IsFixed(true),
+        NumBits(NaClBitsNeededForValue(MaxAbbrev)) {}
+};
+} // End llvm namespace
+
+#endif