add an abbreviation for the string constants opzn, shrinking the constnats

block from:

  Block ID #11 (CONSTANTS_BLOCK):
      Num Instances: 1722
         Total Size: 3.85976e+06b/482470B/120617W
          % of file: 16.7609
       Average Size: 2241.44b/280.18B/70.045W
  Tot/Avg SubBlocks: 0/0
    Tot/Avg Abbrevs: 1/0.00058072
    Tot/Avg Records: 26423/15.3444
      % Abbrev Recs: 69.1746

to:

 Block ID #11 (CONSTANTS_BLOCK):
      Num Instances: 1724
         Total Size: 2.62406e+06b/328008B/82001.9W
          % of file: 12.041
       Average Size: 1522.08b/190.26B/47.5649W
  Tot/Avg SubBlocks: 0/0
    Tot/Avg Abbrevs: 2/0.00116009
    Tot/Avg Records: 26280/15.2436
      % Abbrev Recs: 68.9992

This shrinks kc++ from 2815788 to 2724088 bytes, which means the bitcode
file is now smaller than the bytecode file.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36820 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2007-05-06 00:42:18 +00:00
parent 2d6b4bfc84
commit 817f08a0e5

View File

@ -411,7 +411,7 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
unsigned AggregateAbbrev = 0;
unsigned GEPAbbrev = 0;
unsigned String7Abbrev = 0;
// If this is a constant pool for the module, emit module-specific abbrevs.
if (isGlobal) {
// Abbrev for CST_CODE_AGGREGATE.
@ -420,6 +420,13 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, Log2_32_Ceil(LastVal+1)));
AggregateAbbrev = Stream.EmitAbbrev(Abbv);
// Abbrev for CST_CODE_STRING.
Abbv = new BitCodeAbbrev();
Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
String7Abbrev = Stream.EmitAbbrev(Abbv);
}
// FIXME: Install and use abbrevs to reduce size. Install them globally so
@ -487,9 +494,14 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
} else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
// Emit constant strings specially.
Code = bitc::CST_CODE_STRING;
for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
Record.push_back(cast<ConstantInt>(C->getOperand(i))->getZExtValue());
bool isStr7 = true;
for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i) {
unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
Record.push_back(V);
isStr7 &= (V & 128) == 0;
}
if (isStr7)
AbbrevToUse = String7Abbrev;
} else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
isa<ConstantVector>(V)) {
Code = bitc::CST_CODE_AGGREGATE;
@ -519,7 +531,6 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
Record.push_back(VE.getTypeID(C->getOperand(i)->getType()));
Record.push_back(VE.getValueID(C->getOperand(i)));
}
AbbrevToUse = GEPAbbrev;
break;
case Instruction::Select:
Code = bitc::CST_CODE_CE_SELECT;