update comments, no functionality change

[oota-llvm.git] / include / llvm / Bitcode / BitCodes.h

diff --git a/include/llvm/Bitcode/BitCodes.h b/include/llvm/Bitcode/BitCodes.h
index 15a7a4943dc908582d218af720a7a1666e90a269..59d57e77f2855fc8ee3b52ceeea1adb196f0f46c 100644 (file)
--- a/include/llvm/Bitcode/BitCodes.h
+++ b/include/llvm/Bitcode/BitCodes.h
@@ -30,9 +30,9 @@ namespace bitc {
     BlockSizeWidth = 32  // BlockSize up to 2^32 32-bit words = 32GB per block.
   };
   
-  // The standard code namespace always has a way to exit a block, enter a
+  // The standard abbrev namespace always has a way to exit a block, enter a
   // nested block, define abbrevs, and define an unabbreviated record.
-  enum FixedCodes {
+  enum FixedAbbrevIDs {
     END_BLOCK = 0,  // Must be zero to guarantee termination for broken bitcode.
     ENTER_SUBBLOCK = 1,
 
@@ -48,8 +48,30 @@ namespace bitc {
     UNABBREV_RECORD = 3,
     
     // This is not a code, this is a marker for the first abbrev assignment.
-    FIRST_ABBREV = 4
+    FIRST_APPLICATION_ABBREV = 4
   };
+  
+  /// 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 {
+    BLOCKINFO_CODE_SETBID = 1  // SETBID: [blockid#]
+    // DEFINE_ABBREV has magic semantics here, applying to the current SETBID'd
+    // block, instead of the BlockInfo block.
+    // BLOCKNAME: give string name to block, if desired.
+  };
+  
 } // End bitc namespace
 
 /// BitCodeAbbrevOp - This describes one or more operands in an abbreviation.
@@ -63,12 +85,14 @@ class BitCodeAbbrevOp {
   unsigned Enc   : 3;     // The encoding to use.
 public:
   enum Encoding {
-    FixedWidth = 1,   // A fixed with field, Val specifies number of bits.
-    VBR        = 2   // A VBR field where Val specifies the width of each chunk.
+    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._].
   };
     
   BitCodeAbbrevOp(uint64_t V) :  Val(V), IsLiteral(true) {}
-  BitCodeAbbrevOp(Encoding E, uint64_t Data)
+  BitCodeAbbrevOp(Encoding E, uint64_t Data = 0)
     : Val(Data), IsLiteral(false), Enc(E) {}
   
   bool isLiteral() const { return IsLiteral; }
@@ -79,14 +103,58 @@ public:
   
   // Accessors for encoding info.
   Encoding getEncoding() const { assert(isEncoding()); return (Encoding)Enc; }
-  uint64_t getEncodingData() const { assert(isEncoding()); return Val; }
+  uint64_t getEncodingData() const {
+    assert(isEncoding() && hasEncodingData());
+    return Val;
+  }
   
   bool hasEncodingData() const { return hasEncodingData(getEncoding()); }
   static bool hasEncodingData(Encoding E) {
-    return true; 
+    switch (E) {
+    default: assert(0 && "Unknown encoding");
+    case Fixed:
+    case VBR:
+      return true;
+    case Array:
+    case Char6:
+      return false;
+    }
   }
+  
+  /// 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;
+    assert(0 && "Not a value Char6 character!");
+    return 0;
+  }
+  
+  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 '_';
+    assert(0 && "Not a value Char6 character!");
+    return ' ';
+  }
+  
 };
 
+/// BitCodeAbbrev - 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 BitCodeAbbrev {
   SmallVector<BitCodeAbbrevOp, 8> OperandList;
   unsigned char RefCount; // Number of things using this.