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
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index b1a001e..c4e221f 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -651,12 +651,26 @@
unsigned Size = Record.size();
std::vector<Constant*> Elts;
-
for (unsigned i = 0; i != Size; ++i)
Elts.push_back(ConstantInt::get(EltTy, Record[i]));
V = ConstantArray::get(ATy, Elts);
break;
}
+ case bitc::CST_CODE_CSTRING: { // CSTRING: [values]
+ if (Record.empty())
+ return Error("Invalid CST_AGGREGATE record");
+
+ const ArrayType *ATy = cast<ArrayType>(CurTy);
+ const Type *EltTy = ATy->getElementType();
+
+ unsigned Size = Record.size();
+ std::vector<Constant*> Elts;
+ for (unsigned i = 0; i != Size; ++i)
+ Elts.push_back(ConstantInt::get(EltTy, Record[i]));
+ Elts.push_back(Constant::getNullValue(EltTy));
+ V = ConstantArray::get(ATy, Elts);
+ break;
+ }
case bitc::CST_CODE_CE_BINOP: { // CE_BINOP: [opcode, opval, opval]
if (Record.size() < 3) return Error("Invalid CE_BINOP record");
int Opc = GetDecodedBinaryOpcode(Record[0], CurTy);
diff --git a/lib/Bitcode/Writer/BitcodeWriter.cpp b/lib/Bitcode/Writer/BitcodeWriter.cpp
index 6cfa25a..92475fc 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -411,7 +411,9 @@
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 @@
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 @@
}
} 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;