llvm-6502/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
Chris Lattner 8047d9a6be move an optimization for memcmp out of simplifylibcalls and into
SDISel.  This optimization was causing simplifylibcalls to 
introduce type-unsafe nastiness.  This is the first step, I'll be 
expanding the memcmp optimizations shortly, covering things that
we really really wouldn't want simplifylibcalls to do.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92098 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-24 00:37:38 +00:00

498 lines
17 KiB
C++

//===-- SelectionDAGBuilder.h - Selection-DAG building --------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements routines for translating from LLVM IR into SelectionDAG IR.
//
//===----------------------------------------------------------------------===//
#ifndef SELECTIONDAGBUILDER_H
#define SELECTIONDAGBUILDER_H
#include "llvm/Constants.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/ADT/APInt.h"
#include "llvm/ADT/DenseMap.h"
#ifndef NDEBUG
#include "llvm/ADT/SmallSet.h"
#endif
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Support/ErrorHandling.h"
#include <vector>
#include <set>
namespace llvm {
class AliasAnalysis;
class AllocaInst;
class BasicBlock;
class BitCastInst;
class BranchInst;
class CallInst;
class ExtractElementInst;
class ExtractValueInst;
class FCmpInst;
class FPExtInst;
class FPToSIInst;
class FPToUIInst;
class FPTruncInst;
class Function;
class FunctionLoweringInfo;
class GetElementPtrInst;
class GCFunctionInfo;
class ICmpInst;
class IntToPtrInst;
class IndirectBrInst;
class InvokeInst;
class InsertElementInst;
class InsertValueInst;
class Instruction;
class LoadInst;
class MachineBasicBlock;
class MachineFunction;
class MachineInstr;
class MachineRegisterInfo;
class PHINode;
class PtrToIntInst;
class ReturnInst;
class SDISelAsmOperandInfo;
class SExtInst;
class SelectInst;
class ShuffleVectorInst;
class SIToFPInst;
class StoreInst;
class SwitchInst;
class TargetData;
class TargetLowering;
class TruncInst;
class UIToFPInst;
class UnreachableInst;
class UnwindInst;
class VAArgInst;
class ZExtInst;
//===----------------------------------------------------------------------===//
/// SelectionDAGBuilder - This is the common target-independent lowering
/// implementation that is parameterized by a TargetLowering object.
/// Also, targets can overload any lowering method.
///
class SelectionDAGBuilder {
MachineBasicBlock *CurMBB;
/// CurDebugLoc - current file + line number. Changes as we build the DAG.
DebugLoc CurDebugLoc;
DenseMap<const Value*, SDValue> NodeMap;
public:
/// PendingLoads - Loads are not emitted to the program immediately. We bunch
/// them up and then emit token factor nodes when possible. This allows us to
/// get simple disambiguation between loads without worrying about alias
/// analysis.
SmallVector<SDValue, 8> PendingLoads;
private:
/// PendingExports - CopyToReg nodes that copy values to virtual registers
/// for export to other blocks need to be emitted before any terminator
/// instruction, but they have no other ordering requirements. We bunch them
/// up and the emit a single tokenfactor for them just before terminator
/// instructions.
SmallVector<SDValue, 8> PendingExports;
/// SDNodeOrder - A unique monotonically increasing number used to order the
/// SDNodes we create.
unsigned SDNodeOrder;
/// Case - A struct to record the Value for a switch case, and the
/// case's target basic block.
struct Case {
Constant* Low;
Constant* High;
MachineBasicBlock* BB;
Case() : Low(0), High(0), BB(0) { }
Case(Constant* low, Constant* high, MachineBasicBlock* bb) :
Low(low), High(high), BB(bb) { }
APInt size() const {
const APInt &rHigh = cast<ConstantInt>(High)->getValue();
const APInt &rLow = cast<ConstantInt>(Low)->getValue();
return (rHigh - rLow + 1ULL);
}
};
struct CaseBits {
uint64_t Mask;
MachineBasicBlock* BB;
unsigned Bits;
CaseBits(uint64_t mask, MachineBasicBlock* bb, unsigned bits):
Mask(mask), BB(bb), Bits(bits) { }
};
typedef std::vector<Case> CaseVector;
typedef std::vector<CaseBits> CaseBitsVector;
typedef CaseVector::iterator CaseItr;
typedef std::pair<CaseItr, CaseItr> CaseRange;
/// CaseRec - A struct with ctor used in lowering switches to a binary tree
/// of conditional branches.
struct CaseRec {
CaseRec(MachineBasicBlock *bb, Constant *lt, Constant *ge, CaseRange r) :
CaseBB(bb), LT(lt), GE(ge), Range(r) {}
/// CaseBB - The MBB in which to emit the compare and branch
MachineBasicBlock *CaseBB;
/// LT, GE - If nonzero, we know the current case value must be less-than or
/// greater-than-or-equal-to these Constants.
Constant *LT;
Constant *GE;
/// Range - A pair of iterators representing the range of case values to be
/// processed at this point in the binary search tree.
CaseRange Range;
};
typedef std::vector<CaseRec> CaseRecVector;
/// The comparison function for sorting the switch case values in the vector.
/// WARNING: Case ranges should be disjoint!
struct CaseCmp {
bool operator () (const Case& C1, const Case& C2) {
assert(isa<ConstantInt>(C1.Low) && isa<ConstantInt>(C2.High));
const ConstantInt* CI1 = cast<const ConstantInt>(C1.Low);
const ConstantInt* CI2 = cast<const ConstantInt>(C2.High);
return CI1->getValue().slt(CI2->getValue());
}
};
struct CaseBitsCmp {
bool operator () (const CaseBits& C1, const CaseBits& C2) {
return C1.Bits > C2.Bits;
}
};
size_t Clusterify(CaseVector& Cases, const SwitchInst &SI);
/// CaseBlock - This structure is used to communicate between
/// SelectionDAGBuilder and SDISel for the code generation of additional basic
/// blocks needed by multi-case switch statements.
struct CaseBlock {
CaseBlock(ISD::CondCode cc, Value *cmplhs, Value *cmprhs, Value *cmpmiddle,
MachineBasicBlock *truebb, MachineBasicBlock *falsebb,
MachineBasicBlock *me)
: CC(cc), CmpLHS(cmplhs), CmpMHS(cmpmiddle), CmpRHS(cmprhs),
TrueBB(truebb), FalseBB(falsebb), ThisBB(me) {}
// CC - the condition code to use for the case block's setcc node
ISD::CondCode CC;
// CmpLHS/CmpRHS/CmpMHS - The LHS/MHS/RHS of the comparison to emit.
// Emit by default LHS op RHS. MHS is used for range comparisons:
// If MHS is not null: (LHS <= MHS) and (MHS <= RHS).
Value *CmpLHS, *CmpMHS, *CmpRHS;
// TrueBB/FalseBB - the block to branch to if the setcc is true/false.
MachineBasicBlock *TrueBB, *FalseBB;
// ThisBB - the block into which to emit the code for the setcc and branches
MachineBasicBlock *ThisBB;
};
struct JumpTable {
JumpTable(unsigned R, unsigned J, MachineBasicBlock *M,
MachineBasicBlock *D): Reg(R), JTI(J), MBB(M), Default(D) {}
/// Reg - the virtual register containing the index of the jump table entry
//. to jump to.
unsigned Reg;
/// JTI - the JumpTableIndex for this jump table in the function.
unsigned JTI;
/// MBB - the MBB into which to emit the code for the indirect jump.
MachineBasicBlock *MBB;
/// Default - the MBB of the default bb, which is a successor of the range
/// check MBB. This is when updating PHI nodes in successors.
MachineBasicBlock *Default;
};
struct JumpTableHeader {
JumpTableHeader(APInt F, APInt L, Value* SV, MachineBasicBlock* H,
bool E = false):
First(F), Last(L), SValue(SV), HeaderBB(H), Emitted(E) {}
APInt First;
APInt Last;
Value *SValue;
MachineBasicBlock *HeaderBB;
bool Emitted;
};
typedef std::pair<JumpTableHeader, JumpTable> JumpTableBlock;
struct BitTestCase {
BitTestCase(uint64_t M, MachineBasicBlock* T, MachineBasicBlock* Tr):
Mask(M), ThisBB(T), TargetBB(Tr) { }
uint64_t Mask;
MachineBasicBlock* ThisBB;
MachineBasicBlock* TargetBB;
};
typedef SmallVector<BitTestCase, 3> BitTestInfo;
struct BitTestBlock {
BitTestBlock(APInt F, APInt R, Value* SV,
unsigned Rg, bool E,
MachineBasicBlock* P, MachineBasicBlock* D,
const BitTestInfo& C):
First(F), Range(R), SValue(SV), Reg(Rg), Emitted(E),
Parent(P), Default(D), Cases(C) { }
APInt First;
APInt Range;
Value *SValue;
unsigned Reg;
bool Emitted;
MachineBasicBlock *Parent;
MachineBasicBlock *Default;
BitTestInfo Cases;
};
public:
// TLI - This is information that describes the available target features we
// need for lowering. This indicates when operations are unavailable,
// implemented with a libcall, etc.
TargetLowering &TLI;
SelectionDAG &DAG;
const TargetData *TD;
AliasAnalysis *AA;
/// SwitchCases - Vector of CaseBlock structures used to communicate
/// SwitchInst code generation information.
std::vector<CaseBlock> SwitchCases;
/// JTCases - Vector of JumpTable structures used to communicate
/// SwitchInst code generation information.
std::vector<JumpTableBlock> JTCases;
/// BitTestCases - Vector of BitTestBlock structures used to communicate
/// SwitchInst code generation information.
std::vector<BitTestBlock> BitTestCases;
/// PHINodesToUpdate - A list of phi instructions whose operand list will
/// be updated after processing the current basic block.
std::vector<std::pair<MachineInstr*, unsigned> > PHINodesToUpdate;
/// EdgeMapping - If an edge from CurMBB to any MBB is changed (e.g. due to
/// scheduler custom lowering), track the change here.
DenseMap<MachineBasicBlock*, MachineBasicBlock*> EdgeMapping;
// Emit PHI-node-operand constants only once even if used by multiple
// PHI nodes.
DenseMap<Constant*, unsigned> ConstantsOut;
/// FuncInfo - Information about the function as a whole.
///
FunctionLoweringInfo &FuncInfo;
/// OptLevel - What optimization level we're generating code for.
///
CodeGenOpt::Level OptLevel;
/// GFI - Garbage collection metadata for the function.
GCFunctionInfo *GFI;
/// HasTailCall - This is set to true if a call in the current
/// block has been translated as a tail call. In this case,
/// no subsequent DAG nodes should be created.
///
bool HasTailCall;
LLVMContext *Context;
SelectionDAGBuilder(SelectionDAG &dag, TargetLowering &tli,
FunctionLoweringInfo &funcinfo,
CodeGenOpt::Level ol)
: CurDebugLoc(DebugLoc::getUnknownLoc()), SDNodeOrder(0),
TLI(tli), DAG(dag), FuncInfo(funcinfo), OptLevel(ol),
HasTailCall(false),
Context(dag.getContext()) {
}
void init(GCFunctionInfo *gfi, AliasAnalysis &aa);
/// clear - Clear out the curret SelectionDAG and the associated
/// state and prepare this SelectionDAGBuilder object to be used
/// for a new block. This doesn't clear out information about
/// additional blocks that are needed to complete switch lowering
/// or PHI node updating; that information is cleared out as it is
/// consumed.
void clear();
/// getRoot - Return the current virtual root of the Selection DAG,
/// flushing any PendingLoad items. This must be done before emitting
/// a store or any other node that may need to be ordered after any
/// prior load instructions.
///
SDValue getRoot();
/// getControlRoot - Similar to getRoot, but instead of flushing all the
/// PendingLoad items, flush all the PendingExports items. It is necessary
/// to do this before emitting a terminator instruction.
///
SDValue getControlRoot();
DebugLoc getCurDebugLoc() const { return CurDebugLoc; }
void setCurDebugLoc(DebugLoc dl) { CurDebugLoc = dl; }
unsigned getSDNodeOrder() const { return SDNodeOrder; }
void CopyValueToVirtualRegister(Value *V, unsigned Reg);
void visit(Instruction &I);
void visit(unsigned Opcode, User &I);
void setCurrentBasicBlock(MachineBasicBlock *MBB) { CurMBB = MBB; }
SDValue getValue(const Value *V);
void setValue(const Value *V, SDValue NewN) {
SDValue &N = NodeMap[V];
assert(N.getNode() == 0 && "Already set a value for this node!");
N = NewN;
}
void GetRegistersForValue(SDISelAsmOperandInfo &OpInfo,
std::set<unsigned> &OutputRegs,
std::set<unsigned> &InputRegs);
void FindMergedConditions(Value *Cond, MachineBasicBlock *TBB,
MachineBasicBlock *FBB, MachineBasicBlock *CurBB,
unsigned Opc);
void EmitBranchForMergedCondition(Value *Cond, MachineBasicBlock *TBB,
MachineBasicBlock *FBB,
MachineBasicBlock *CurBB);
bool ShouldEmitAsBranches(const std::vector<CaseBlock> &Cases);
bool isExportableFromCurrentBlock(Value *V, const BasicBlock *FromBB);
void CopyToExportRegsIfNeeded(Value *V);
void ExportFromCurrentBlock(Value *V);
void LowerCallTo(CallSite CS, SDValue Callee, bool IsTailCall,
MachineBasicBlock *LandingPad = NULL);
private:
// Terminator instructions.
void visitRet(ReturnInst &I);
void visitBr(BranchInst &I);
void visitSwitch(SwitchInst &I);
void visitIndirectBr(IndirectBrInst &I);
void visitUnreachable(UnreachableInst &I) { /* noop */ }
// Helpers for visitSwitch
bool handleSmallSwitchRange(CaseRec& CR,
CaseRecVector& WorkList,
Value* SV,
MachineBasicBlock* Default);
bool handleJTSwitchCase(CaseRec& CR,
CaseRecVector& WorkList,
Value* SV,
MachineBasicBlock* Default);
bool handleBTSplitSwitchCase(CaseRec& CR,
CaseRecVector& WorkList,
Value* SV,
MachineBasicBlock* Default);
bool handleBitTestsSwitchCase(CaseRec& CR,
CaseRecVector& WorkList,
Value* SV,
MachineBasicBlock* Default);
public:
void visitSwitchCase(CaseBlock &CB);
void visitBitTestHeader(BitTestBlock &B);
void visitBitTestCase(MachineBasicBlock* NextMBB,
unsigned Reg,
BitTestCase &B);
void visitJumpTable(JumpTable &JT);
void visitJumpTableHeader(JumpTable &JT, JumpTableHeader &JTH);
private:
// These all get lowered before this pass.
void visitInvoke(InvokeInst &I);
void visitUnwind(UnwindInst &I);
void visitBinary(User &I, unsigned OpCode);
void visitShift(User &I, unsigned Opcode);
void visitAdd(User &I) { visitBinary(I, ISD::ADD); }
void visitFAdd(User &I) { visitBinary(I, ISD::FADD); }
void visitSub(User &I) { visitBinary(I, ISD::SUB); }
void visitFSub(User &I);
void visitMul(User &I) { visitBinary(I, ISD::MUL); }
void visitFMul(User &I) { visitBinary(I, ISD::FMUL); }
void visitURem(User &I) { visitBinary(I, ISD::UREM); }
void visitSRem(User &I) { visitBinary(I, ISD::SREM); }
void visitFRem(User &I) { visitBinary(I, ISD::FREM); }
void visitUDiv(User &I) { visitBinary(I, ISD::UDIV); }
void visitSDiv(User &I) { visitBinary(I, ISD::SDIV); }
void visitFDiv(User &I) { visitBinary(I, ISD::FDIV); }
void visitAnd (User &I) { visitBinary(I, ISD::AND); }
void visitOr (User &I) { visitBinary(I, ISD::OR); }
void visitXor (User &I) { visitBinary(I, ISD::XOR); }
void visitShl (User &I) { visitShift(I, ISD::SHL); }
void visitLShr(User &I) { visitShift(I, ISD::SRL); }
void visitAShr(User &I) { visitShift(I, ISD::SRA); }
void visitICmp(User &I);
void visitFCmp(User &I);
// Visit the conversion instructions
void visitTrunc(User &I);
void visitZExt(User &I);
void visitSExt(User &I);
void visitFPTrunc(User &I);
void visitFPExt(User &I);
void visitFPToUI(User &I);
void visitFPToSI(User &I);
void visitUIToFP(User &I);
void visitSIToFP(User &I);
void visitPtrToInt(User &I);
void visitIntToPtr(User &I);
void visitBitCast(User &I);
void visitExtractElement(User &I);
void visitInsertElement(User &I);
void visitShuffleVector(User &I);
void visitExtractValue(ExtractValueInst &I);
void visitInsertValue(InsertValueInst &I);
void visitGetElementPtr(User &I);
void visitSelect(User &I);
void visitAlloca(AllocaInst &I);
void visitLoad(LoadInst &I);
void visitStore(StoreInst &I);
void visitPHI(PHINode &I) { } // PHI nodes are handled specially.
void visitCall(CallInst &I);
bool visitMemCmpCall(CallInst &I);
void visitInlineAsm(CallSite CS);
const char *visitIntrinsicCall(CallInst &I, unsigned Intrinsic);
void visitTargetIntrinsic(CallInst &I, unsigned Intrinsic);
void visitPow(CallInst &I);
void visitExp2(CallInst &I);
void visitExp(CallInst &I);
void visitLog(CallInst &I);
void visitLog2(CallInst &I);
void visitLog10(CallInst &I);
void visitVAStart(CallInst &I);
void visitVAArg(VAArgInst &I);
void visitVAEnd(CallInst &I);
void visitVACopy(CallInst &I);
void visitUserOp1(Instruction &I) {
llvm_unreachable("UserOp1 should not exist at instruction selection time!");
}
void visitUserOp2(Instruction &I) {
llvm_unreachable("UserOp2 should not exist at instruction selection time!");
}
const char *implVisitBinaryAtomic(CallInst& I, ISD::NodeType Op);
const char *implVisitAluOverflow(CallInst &I, ISD::NodeType Op);
};
} // end namespace llvm
#endif