//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
-// The LowerSwitch transformation rewrites switch statements with a sequence of
-// branches, which allows targets to get away with not implementing the switch
-// statement until it is convenient.
+// The LowerSwitch transformation rewrites switch instructions with a sequence
+// of branches, which allows targets to get away with not implementing the
+// switch instruction until it is convenient.
//
//===----------------------------------------------------------------------===//
#include "llvm/Constants.h"
#include "llvm/Function.h"
#include "llvm/Instructions.h"
+#include "llvm/LLVMContext.h"
#include "llvm/Pass.h"
-#include "llvm/Support/Debug.h"
+#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
#include <algorithm>
using namespace llvm;
namespace {
/// LowerSwitch Pass - Replace all SwitchInst instructions with chained branch
- /// instructions. Note that this cannot be a BasicBlock pass because it
- /// modifies the CFG!
- class VISIBILITY_HIDDEN LowerSwitch : public FunctionPass {
+ /// instructions.
+ class LowerSwitch : public FunctionPass {
public:
- static const int ID; // Pass identifcation, replacement for typeid
- LowerSwitch() : FunctionPass((intptr_t) &ID) {}
+ static char ID; // Pass identification, replacement for typeid
+ LowerSwitch() : FunctionPass(ID) {
+ initializeLowerSwitchPass(*PassRegistry::getPassRegistry());
+ }
virtual bool runOnFunction(Function &F);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
// This is a cluster of orthogonal Transforms
AU.addPreserved<UnifyFunctionExitNodes>();
- AU.addPreservedID(PromoteMemoryToRegisterID);
- AU.addPreservedID(LowerSelectID);
+ AU.addPreserved("mem2reg");
AU.addPreservedID(LowerInvokePassID);
- AU.addPreservedID(LowerAllocationsID);
}
struct CaseRange {
Constant* High;
BasicBlock* BB;
- CaseRange() : Low(0), High(0), BB(0) { }
- CaseRange(Constant* low, Constant* high, BasicBlock* bb) :
+ CaseRange(Constant *low = 0, Constant *high = 0, BasicBlock *bb = 0) :
Low(low), High(high), BB(bb) { }
};
BasicBlock* OrigBlock, BasicBlock* Default);
unsigned Clusterify(CaseVector& Cases, SwitchInst *SI);
};
-
- /// The comparison function for sorting the switch case values in the vector.
- /// WARNING: Case ranges should be disjoint!
- struct CaseCmp {
- bool operator () (const LowerSwitch::CaseRange& C1,
- const LowerSwitch::CaseRange& C2) {
-
- const ConstantInt* CI1 = cast<const ConstantInt>(C1.Low);
- const ConstantInt* CI2 = cast<const ConstantInt>(C2.High);
- return CI1->getValue().slt(CI2->getValue());
- }
- };
-
- const int LowerSwitch::ID = 0;
- RegisterPass<LowerSwitch>
- X("lowerswitch", "Lower SwitchInst's to branches");
}
-// Publically exposed interface to pass...
-const PassInfo *llvm::LowerSwitchID = X.getPassInfo();
+char LowerSwitch::ID = 0;
+INITIALIZE_PASS(LowerSwitch, "lowerswitch",
+ "Lower SwitchInst's to branches", false, false)
+
+// Publicly exposed interface to pass...
+char &llvm::LowerSwitchID = LowerSwitch::ID;
// createLowerSwitchPass - Interface to this file...
FunctionPass *llvm::createLowerSwitchPass() {
return new LowerSwitch();
// operator<< - Used for debugging purposes.
//
-static std::ostream& operator<<(std::ostream &O,
- const LowerSwitch::CaseVector &C) {
+static raw_ostream& operator<<(raw_ostream &O,
+ const LowerSwitch::CaseVector &C)
+ LLVM_ATTRIBUTE_USED;
+static raw_ostream& operator<<(raw_ostream &O,
+ const LowerSwitch::CaseVector &C) {
O << "[";
for (LowerSwitch::CaseVector::const_iterator B = C.begin(),
return O << "]";
}
-static OStream& operator<<(OStream &O, const LowerSwitch::CaseVector &C) {
- if (O.stream()) *O.stream() << C;
- return O;
-}
-
// switchConvert - Convert the switch statement into a binary lookup of
// the case values. The function recursively builds this tree.
//
unsigned Mid = Size / 2;
std::vector<CaseRange> LHS(Begin, Begin + Mid);
- DOUT << "LHS: " << LHS << "\n";
+ DEBUG(dbgs() << "LHS: " << LHS << "\n");
std::vector<CaseRange> RHS(Begin + Mid, End);
- DOUT << "RHS: " << RHS << "\n";
+ DEBUG(dbgs() << "RHS: " << RHS << "\n");
CaseRange& Pivot = *(Begin + Mid);
- DEBUG( DOUT << "Pivot ==> "
- << cast<ConstantInt>(Pivot.Low)->getValue().toStringSigned(10)
- << " -"
- << cast<ConstantInt>(Pivot.High)->getValue().toStringSigned(10)
- << "\n");
+ DEBUG(dbgs() << "Pivot ==> "
+ << cast<ConstantInt>(Pivot.Low)->getValue() << " -"
+ << cast<ConstantInt>(Pivot.High)->getValue() << "\n");
BasicBlock* LBranch = switchConvert(LHS.begin(), LHS.end(), Val,
OrigBlock, Default);
// Create a new node that checks if the value is < pivot. Go to the
// left branch if it is and right branch if not.
Function* F = OrigBlock->getParent();
- BasicBlock* NewNode = new BasicBlock("NodeBlock");
+ BasicBlock* NewNode = BasicBlock::Create(Val->getContext(), "NodeBlock");
Function::iterator FI = OrigBlock;
F->getBasicBlockList().insert(++FI, NewNode);
- ICmpInst* Comp = new ICmpInst(ICmpInst::ICMP_SLT, Val, Pivot.Low, "Pivot");
+ ICmpInst* Comp = new ICmpInst(ICmpInst::ICMP_ULT,
+ Val, Pivot.Low, "Pivot");
NewNode->getInstList().push_back(Comp);
- new BranchInst(LBranch, RBranch, Comp, NewNode);
+ BranchInst::Create(LBranch, RBranch, Comp, NewNode);
return NewNode;
}
BasicBlock* Default)
{
Function* F = OrigBlock->getParent();
- BasicBlock* NewLeaf = new BasicBlock("LeafBlock");
+ BasicBlock* NewLeaf = BasicBlock::Create(Val->getContext(), "LeafBlock");
Function::iterator FI = OrigBlock;
F->getBasicBlockList().insert(++FI, NewLeaf);
ICmpInst* Comp = NULL;
if (Leaf.Low == Leaf.High) {
// Make the seteq instruction...
- Comp = new ICmpInst(ICmpInst::ICMP_EQ, Val, Leaf.Low,
- "SwitchLeaf", NewLeaf);
+ Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_EQ, Val,
+ Leaf.Low, "SwitchLeaf");
} else {
// Make range comparison
if (cast<ConstantInt>(Leaf.Low)->isMinValue(true /*isSigned*/)) {
// Val >= Min && Val <= Hi --> Val <= Hi
- Comp = new ICmpInst(ICmpInst::ICMP_SLE, Val, Leaf.High,
- "SwitchLeaf", NewLeaf);
+ Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_SLE, Val, Leaf.High,
+ "SwitchLeaf");
} else if (cast<ConstantInt>(Leaf.Low)->isZero()) {
// Val >= 0 && Val <= Hi --> Val <=u Hi
- Comp = new ICmpInst(ICmpInst::ICMP_ULE, Val, Leaf.High,
- "SwitchLeaf", NewLeaf);
+ Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_ULE, Val, Leaf.High,
+ "SwitchLeaf");
} else {
// Emit V-Lo <=u Hi-Lo
Constant* NegLo = ConstantExpr::getNeg(Leaf.Low);
- Instruction* Add = BinaryOperator::createAdd(Val, NegLo,
+ Instruction* Add = BinaryOperator::CreateAdd(Val, NegLo,
Val->getName()+".off",
NewLeaf);
Constant *UpperBound = ConstantExpr::getAdd(NegLo, Leaf.High);
- Comp = new ICmpInst(ICmpInst::ICMP_ULE, Add, UpperBound,
- "SwitchLeaf", NewLeaf);
+ Comp = new ICmpInst(*NewLeaf, ICmpInst::ICMP_ULE, Add, UpperBound,
+ "SwitchLeaf");
}
}
// Make the conditional branch...
BasicBlock* Succ = Leaf.BB;
- new BranchInst(Succ, Default, Comp, NewLeaf);
+ BranchInst::Create(Succ, Default, Comp, NewLeaf);
// If there were any PHI nodes in this successor, rewrite one entry
// from OrigBlock to come from NewLeaf.
// Clusterify - Transform simple list of Cases into list of CaseRange's
unsigned LowerSwitch::Clusterify(CaseVector& Cases, SwitchInst *SI) {
- unsigned numCmps = 0;
- // Start with "simple" cases
- for (unsigned i = 1; i < SI->getNumSuccessors(); ++i)
- Cases.push_back(CaseRange(SI->getSuccessorValue(i),
- SI->getSuccessorValue(i),
- SI->getSuccessor(i)));
- sort(Cases.begin(), Cases.end(), CaseCmp());
-
- // Merge case into clusters
- if (Cases.size()>=2)
- for (CaseItr I=Cases.begin(), J=++(Cases.begin()), E=Cases.end(); J!=E; ) {
- int64_t nextValue = cast<ConstantInt>(J->Low)->getSExtValue();
- int64_t currentValue = cast<ConstantInt>(I->High)->getSExtValue();
- BasicBlock* nextBB = J->BB;
- BasicBlock* currentBB = I->BB;
-
- // If the two neighboring cases go to the same destination, merge them
- // into a single case.
- if ((nextValue-currentValue==1) && (currentBB == nextBB)) {
- I->High = J->High;
- J = Cases.erase(J);
- } else {
- I = J++;
- }
- }
+ IntegersSubsetToBB TheClusterifier;
- for (CaseItr I=Cases.begin(), E=Cases.end(); I!=E; ++I, ++numCmps) {
- if (I->Low != I->High)
+ // Start with "simple" cases
+ for (SwitchInst::CaseIt i = SI->case_begin(), e = SI->case_end();
+ i != e; ++i) {
+ BasicBlock *SuccBB = i.getCaseSuccessor();
+ IntegersSubset CaseRanges = i.getCaseValueEx();
+ TheClusterifier.add(CaseRanges, SuccBB);
+ }
+
+ TheClusterifier.optimize();
+
+ size_t numCmps = 0;
+ for (IntegersSubsetToBB::RangeIterator i = TheClusterifier.begin(),
+ e = TheClusterifier.end(); i != e; ++i, ++numCmps) {
+ IntegersSubsetToBB::Cluster &C = *i;
+
+ // FIXME: Currently work with ConstantInt based numbers.
+ // Changing it to APInt based is a pretty heavy for this commit.
+ Cases.push_back(CaseRange(C.first.getLow().toConstantInt(),
+ C.first.getHigh().toConstantInt(), C.second));
+ if (C.first.isSingleNumber())
// A range counts double, since it requires two compares.
++numCmps;
}
- return numCmps;
+ return numCmps;
}
// processSwitchInst - Replace the specified switch instruction with a sequence
BasicBlock *CurBlock = SI->getParent();
BasicBlock *OrigBlock = CurBlock;
Function *F = CurBlock->getParent();
- Value *Val = SI->getOperand(0); // The value we are switching on...
+ Value *Val = SI->getCondition(); // The value we are switching on...
BasicBlock* Default = SI->getDefaultDest();
// If there is only the default destination, don't bother with the code below.
- if (SI->getNumOperands() == 2) {
- new BranchInst(SI->getDefaultDest(), CurBlock);
+ if (!SI->getNumCases()) {
+ BranchInst::Create(SI->getDefaultDest(), CurBlock);
CurBlock->getInstList().erase(SI);
return;
}
// Create a new, empty default block so that the new hierarchy of
// if-then statements go to this and the PHI nodes are happy.
- BasicBlock* NewDefault = new BasicBlock("NewDefault");
+ BasicBlock* NewDefault = BasicBlock::Create(SI->getContext(), "NewDefault");
F->getBasicBlockList().insert(Default, NewDefault);
- new BranchInst(Default, NewDefault);
+ BranchInst::Create(Default, NewDefault);
// If there is an entry in any PHI nodes for the default edge, make sure
// to update them as well.
CaseVector Cases;
unsigned numCmps = Clusterify(Cases, SI);
- DOUT << "Clusterify finished. Total clusters: " << Cases.size()
- << ". Total compares: " << numCmps << "\n";
- DOUT << "Cases: " << Cases << "\n";
+ DEBUG(dbgs() << "Clusterify finished. Total clusters: " << Cases.size()
+ << ". Total compares: " << numCmps << "\n");
+ DEBUG(dbgs() << "Cases: " << Cases << "\n");
+ (void)numCmps;
BasicBlock* SwitchBlock = switchConvert(Cases.begin(), Cases.end(), Val,
OrigBlock, NewDefault);
// Branch to our shiny new if-then stuff...
- new BranchInst(SwitchBlock, OrigBlock);
+ BranchInst::Create(SwitchBlock, OrigBlock);
// We are now done with the switch instruction, delete it.
CurBlock->getInstList().erase(SI);
projects / oota-llvm.git / blobdiff