Changes in directory llvm/lib/Bitcode/Writer:
BitcodeWriter.cpp updated: 1.41 -> 1.42
---
Log message:
stop encoding type/value pairs when the type is implied by the value.
This shrinks the function block of kc++ from 1055K to 906K
---
Diffs of the changes: (+48 -35)
BitcodeWriter.cpp | 83 +++++++++++++++++++++++++++++++-----------------------
1 files changed, 48 insertions(+), 35 deletions(-)
Index: llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
diff -u llvm/lib/Bitcode/Writer/BitcodeWriter.cpp:1.41
llvm/lib/Bitcode/Writer/BitcodeWriter.cpp:1.42
--- llvm/lib/Bitcode/Writer/BitcodeWriter.cpp:1.41 Sat May 5 02:44:49 2007
+++ llvm/lib/Bitcode/Writer/BitcodeWriter.cpp Sat May 5 19:00:00 2007
@@ -572,9 +572,29 @@
}
}
+/// PushValueAndType - The file has to encode both the value and type id for
+/// many values, because we need to know what type to create for forward
+/// references. However, most operands are not forward references, so this
type
+/// field is not needed.
+///
+/// This function adds V's value ID to Vals. If the value ID is higher than
the
+/// instruction ID, then it is a forward reference, and it also includes the
+/// type ID.
+static bool PushValueAndType(Value *V, unsigned InstID,
+ SmallVector<unsigned, 64> &Vals,
+ ValueEnumerator &VE) {
+ unsigned ValID = VE.getValueID(V);
+ Vals.push_back(ValID);
+ if (ValID >= InstID) {
+ Vals.push_back(VE.getTypeID(V->getType()));
+ return true;
+ }
+ return false;
+}
+
/// WriteInstruction - Emit an instruction to the specified stream.
-static void WriteInstruction(const Instruction &I, ValueEnumerator &VE,
- BitstreamWriter &Stream,
+static void WriteInstruction(const Instruction &I, unsigned InstID,
+ ValueEnumerator &VE, BitstreamWriter &Stream,
SmallVector<unsigned, 64> &Vals) {
unsigned Code = 0;
unsigned AbbrevToUse = 0;
@@ -598,10 +618,8 @@
case Instruction::GetElementPtr:
Code = bitc::FUNC_CODE_INST_GEP;
- for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i) {
- Vals.push_back(VE.getTypeID(I.getOperand(i)->getType()));
- Vals.push_back(VE.getValueID(I.getOperand(i)));
- }
+ for (unsigned i = 0, e = I.getNumOperands(); i != e; ++i)
+ PushValueAndType(I.getOperand(i), InstID, Vals, VE);
break;
case Instruction::Select:
Code = bitc::FUNC_CODE_INST_SELECT;
@@ -633,18 +651,15 @@
case Instruction::ICmp:
case Instruction::FCmp:
Code = bitc::FUNC_CODE_INST_CMP;
- Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
- Vals.push_back(VE.getValueID(I.getOperand(0)));
+ PushValueAndType(I.getOperand(0), InstID, Vals, VE);
Vals.push_back(VE.getValueID(I.getOperand(1)));
Vals.push_back(cast<CmpInst>(I).getPredicate());
break;
case Instruction::Ret:
Code = bitc::FUNC_CODE_INST_RET;
- if (I.getNumOperands()) {
- Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
- Vals.push_back(VE.getValueID(I.getOperand(0)));
- }
+ if (I.getNumOperands())
+ PushValueAndType(I.getOperand(0), InstID, Vals, VE);
break;
case Instruction::Br:
Code = bitc::FUNC_CODE_INST_BR;
@@ -663,10 +678,9 @@
case Instruction::Invoke: {
Code = bitc::FUNC_CODE_INST_INVOKE;
Vals.push_back(cast<InvokeInst>(I).getCallingConv());
- Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
- Vals.push_back(VE.getValueID(I.getOperand(0))); // callee
- Vals.push_back(VE.getValueID(I.getOperand(1))); // normal
- Vals.push_back(VE.getValueID(I.getOperand(2))); // unwind
+ Vals.push_back(VE.getValueID(I.getOperand(1))); // normal dest
+ Vals.push_back(VE.getValueID(I.getOperand(2))); // unwind dest
+ PushValueAndType(I.getOperand(0), InstID, Vals, VE); // callee
// Emit value #'s for the fixed parameters.
const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
@@ -676,12 +690,9 @@
// Emit type/value pairs for varargs params.
if (FTy->isVarArg()) {
- unsigned NumVarargs = I.getNumOperands()-3-FTy->getNumParams();
- for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
- i != e; ++i) {
- Vals.push_back(VE.getTypeID(I.getOperand(i)->getType()));
- Vals.push_back(VE.getValueID(I.getOperand(i)));
- }
+ for (unsigned i = 3+FTy->getNumParams(), e = I.getNumOperands();
+ i != e; ++i)
+ PushValueAndType(I.getOperand(i), InstID, Vals, VE); // vararg
}
break;
}
@@ -721,11 +732,11 @@
case Instruction::Load:
Code = bitc::FUNC_CODE_INST_LOAD;
- Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
- Vals.push_back(VE.getValueID(I.getOperand(0))); // ptr.
+ if (!PushValueAndType(I.getOperand(0), InstID, Vals, VE)) // ptr
+ AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
+
Vals.push_back(Log2_32(cast<LoadInst>(I).getAlignment())+1);
Vals.push_back(cast<LoadInst>(I).isVolatile());
- AbbrevToUse = FUNCTION_INST_LOAD_ABBREV;
break;
case Instruction::Store:
Code = bitc::FUNC_CODE_INST_STORE;
@@ -739,8 +750,7 @@
Code = bitc::FUNC_CODE_INST_CALL;
Vals.push_back((cast<CallInst>(I).getCallingConv() << 1) |
cast<CallInst>(I).isTailCall());
- Vals.push_back(VE.getTypeID(I.getOperand(0)->getType()));
- Vals.push_back(VE.getValueID(I.getOperand(0))); // callee
+ PushValueAndType(I.getOperand(0), InstID, Vals, VE); // Callee
// Emit value #'s for the fixed parameters.
const PointerType *PTy = cast<PointerType>(I.getOperand(0)->getType());
@@ -752,10 +762,8 @@
if (FTy->isVarArg()) {
unsigned NumVarargs = I.getNumOperands()-1-FTy->getNumParams();
for (unsigned i = I.getNumOperands()-NumVarargs, e = I.getNumOperands();
- i != e; ++i) {
- Vals.push_back(VE.getTypeID(I.getOperand(i)->getType()));
- Vals.push_back(VE.getValueID(I.getOperand(i)));
- }
+ i != e; ++i)
+ PushValueAndType(I.getOperand(i), InstID, Vals, VE); // varargs
}
break;
}
@@ -850,10 +858,17 @@
VE.getFunctionConstantRange(CstStart, CstEnd);
WriteConstants(CstStart, CstEnd, VE, Stream, false);
+ // Keep a running idea of what the instruction ID is.
+ unsigned InstID = CstEnd;
+
// Finally, emit all the instructions, in order.
for (Function::const_iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
- for (BasicBlock::const_iterator I = BB->begin(), E = BB->end(); I != E;
++I)
- WriteInstruction(*I, VE, Stream, Vals);
+ for (BasicBlock::const_iterator I = BB->begin(), E = BB->end();
+ I != E; ++I) {
+ WriteInstruction(*I, InstID, VE, Stream, Vals);
+ if (I->getType() != Type::VoidTy)
+ ++InstID;
+ }
// Emit names for all the instructions etc.
WriteValueSymbolTable(F.getValueSymbolTable(), VE, Stream);
@@ -997,8 +1012,6 @@
{ // INST_LOAD abbrev for FUNCTION_BLOCK.
BitCodeAbbrev *Abbv = new BitCodeAbbrev();
Abbv->Add(BitCodeAbbrevOp(bitc::FUNC_CODE_INST_LOAD));
- Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, // typeid
- Log2_32_Ceil(VE.getTypes().size()+1)));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 6)); // Ptr
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // Align
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Fixed, 1)); // volatile
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