add a denser encoding for null terminated strings, add a 6-bit abbrev as

well.  This shrinks kc++ from 2724088 to 2717360 bytes.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36821 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2007-05-06 00:53:07 +00:00
parent 817f08a0e5
commit cb3d91b05b
4 changed files with 62 additions and 17 deletions

View File

@ -411,7 +411,9 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
Stream.EnterSubblock(bitc::CONSTANTS_BLOCK_ID, 4);
unsigned AggregateAbbrev = 0;
unsigned String7Abbrev = 0;
unsigned String8Abbrev = 0;
unsigned CString7Abbrev = 0;
unsigned CString6Abbrev = 0;
// If this is a constant pool for the module, emit module-specific abbrevs.
if (isGlobal) {
// Abbrev for CST_CODE_AGGREGATE.
@ -425,8 +427,20 @@ static void WriteConstants(unsigned FirstVal, unsigned LastVal,
Abbv = new BitCodeAbbrev();
Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_STRING));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 8));
String8Abbrev = Stream.EmitAbbrev(Abbv);
// Abbrev for CST_CODE_CSTRING.
Abbv = new BitCodeAbbrev();
Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 7));
String7Abbrev = Stream.EmitAbbrev(Abbv);
CString7Abbrev = Stream.EmitAbbrev(Abbv);
// Abbrev for CST_CODE_CSTRING.
Abbv = new BitCodeAbbrev();
Abbv->Add(BitCodeAbbrevOp(bitc::CST_CODE_CSTRING));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Char6));
CString6Abbrev = Stream.EmitAbbrev(Abbv);
}
// FIXME: Install and use abbrevs to reduce size. Install them globally so
@ -493,15 +507,29 @@ 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;
bool isStr7 = true;
for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i) {
unsigned NumOps = C->getNumOperands();
// If this is a null-terminated string, use the denser CSTRING encoding.
if (C->getOperand(NumOps-1)->isNullValue()) {
Code = bitc::CST_CODE_CSTRING;
--NumOps; // Don't encode the null, which isn't allowed by char6.
} else {
Code = bitc::CST_CODE_STRING;
AbbrevToUse = String8Abbrev;
}
bool isCStr7 = Code == bitc::CST_CODE_CSTRING;
bool isCStrChar6 = Code == bitc::CST_CODE_CSTRING;
for (unsigned i = 0; i != NumOps; ++i) {
unsigned char V = cast<ConstantInt>(C->getOperand(i))->getZExtValue();
Record.push_back(V);
isStr7 &= (V & 128) == 0;
isCStr7 &= (V & 128) == 0;
if (isCStrChar6)
isCStrChar6 = BitCodeAbbrevOp::isChar6(V);
}
if (isStr7)
AbbrevToUse = String7Abbrev;
if (isCStrChar6)
AbbrevToUse = CString6Abbrev;
else if (isCStr7)
AbbrevToUse = CString7Abbrev;
} else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
isa<ConstantVector>(V)) {
Code = bitc::CST_CODE_AGGREGATE;