implement the 'string constant' optimization. This shrinks kc.bit from
2878544 to 2815788
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36818 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index 5a7c84d..b1a001e 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -642,7 +642,21 @@
}
break;
}
+ case bitc::CST_CODE_STRING: { // STRING: [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]));
+ 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 7198bc0..a29f23d 100644
--- a/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -484,6 +484,12 @@
assert (CFP->getType() == Type::DoubleTy && "Unknown FP type!");
Record.push_back(DoubleToBits((double)CFP->getValue()));
}
+ } 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());
+
} else if (isa<ConstantArray>(C) || isa<ConstantStruct>(V) ||
isa<ConstantVector>(V)) {
Code = bitc::CST_CODE_AGGREGATE;
diff --git a/lib/Bitcode/Writer/ValueEnumerator.cpp b/lib/Bitcode/Writer/ValueEnumerator.cpp
index 6b753b2..ae9e67c 100644
--- a/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -12,6 +12,7 @@
//===----------------------------------------------------------------------===//
#include "ValueEnumerator.h"
+#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Module.h"
#include "llvm/TypeSymbolTable.h"
@@ -65,8 +66,6 @@
I != E; ++I)
EnumerateValue(I->getAliasee());
- // FIXME: Implement the 'string constant' optimization.
-
// Enumerate types used by the type symbol table.
EnumerateTypeSymbolTable(M->getTypeSymbolTable());
@@ -105,8 +104,6 @@
// Now that we rearranged the type table, rebuild TypeMap.
for (unsigned i = 0, e = Types.size(); i != e; ++i)
TypeMap[Types[i].first] = i+1;
-
- // FIXME: Sort value tables by frequency.
}
// Optimize constant ordering.
@@ -176,6 +173,10 @@
if (const Constant *C = dyn_cast<Constant>(V)) {
if (isa<GlobalValue>(C)) {
// Initializers for globals are handled explicitly elsewhere.
+ } else if (isa<ConstantArray>(C) && cast<ConstantArray>(C)->isString()) {
+ // Do not enumerate the initializers for an array of simple characters.
+ // The initializers just polute the value table, and we emit the strings
+ // specially.
} else {
// This makes sure that if a constant has uses (for example an array of
// const ints), that they are inserted also.