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llvm-mirror/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
Bill Wendling 40a162f75f Instead of passing in an unsigned value for the optimization level, use an enum, 
which better identifies what the optimization is doing. And is more flexible for
future uses.

llvm-svn: 70440
2009-04-29 23:29:43 +00:00

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19 KiB
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//===-- SelectionDAGBuild.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 SELECTIONDAGBUILD_H
#define SELECTIONDAGBUILD_H
#include "llvm/Constants.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/Target/TargetMachine.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 FreeInst;
class Function;
class GetElementPtrInst;
class GCFunctionInfo;
class ICmpInst;
class IntToPtrInst;
class InvokeInst;
class InsertElementInst;
class InsertValueInst;
class Instruction;
class LoadInst;
class MachineBasicBlock;
class MachineFunction;
class MachineInstr;
class MachineModuleInfo;
class MachineRegisterInfo;
class MallocInst;
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 VICmpInst;
class VFCmpInst;
class VAArgInst;
class ZExtInst;
//===--------------------------------------------------------------------===//
/// FunctionLoweringInfo - This contains information that is global to a
/// function that is used when lowering a region of the function.
///
class FunctionLoweringInfo {
public:
TargetLowering &TLI;
Function *Fn;
MachineFunction *MF;
MachineRegisterInfo *RegInfo;
explicit FunctionLoweringInfo(TargetLowering &TLI);
/// set - Initialize this FunctionLoweringInfo with the given Function
/// and its associated MachineFunction.
///
void set(Function &Fn, MachineFunction &MF, SelectionDAG &DAG,
bool EnableFastISel);
/// MBBMap - A mapping from LLVM basic blocks to their machine code entry.
DenseMap<const BasicBlock*, MachineBasicBlock *> MBBMap;
/// ValueMap - Since we emit code for the function a basic block at a time,
/// we must remember which virtual registers hold the values for
/// cross-basic-block values.
DenseMap<const Value*, unsigned> ValueMap;
/// StaticAllocaMap - Keep track of frame indices for fixed sized allocas in
/// the entry block. This allows the allocas to be efficiently referenced
/// anywhere in the function.
DenseMap<const AllocaInst*, int> StaticAllocaMap;
#ifndef NDEBUG
SmallSet<Instruction*, 8> CatchInfoLost;
SmallSet<Instruction*, 8> CatchInfoFound;
#endif
unsigned MakeReg(MVT VT);
/// isExportedInst - Return true if the specified value is an instruction
/// exported from its block.
bool isExportedInst(const Value *V) {
return ValueMap.count(V);
}
unsigned CreateRegForValue(const Value *V);
unsigned InitializeRegForValue(const Value *V) {
unsigned &R = ValueMap[V];
assert(R == 0 && "Already initialized this value register!");
return R = CreateRegForValue(V);
}
struct LiveOutInfo {
unsigned NumSignBits;
APInt KnownOne, KnownZero;
LiveOutInfo() : NumSignBits(0), KnownOne(1, 0), KnownZero(1, 0) {}
};
/// LiveOutRegInfo - Information about live out vregs, indexed by their
/// register number offset by 'FirstVirtualRegister'.
std::vector<LiveOutInfo> LiveOutRegInfo;
/// clear - Clear out all the function-specific state. This returns this
/// FunctionLoweringInfo to an empty state, ready to be used for a
/// different function.
void clear() {
MBBMap.clear();
ValueMap.clear();
StaticAllocaMap.clear();
#ifndef NDEBUG
CatchInfoLost.clear();
CatchInfoFound.clear();
#endif
LiveOutRegInfo.clear();
}
};
//===----------------------------------------------------------------------===//
/// SelectionDAGLowering - This is the common target-independent lowering
/// implementation that is parameterized by a TargetLowering object.
/// Also, targets can overload any lowering method.
///
class SelectionDAGLowering {
MachineBasicBlock *CurMBB;
/// CurDebugLoc - current file + line number. Changes as we build the DAG.
DebugLoc CurDebugLoc;
DenseMap<const Value*, SDValue> NodeMap;
/// 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;
/// 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;
/// 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) { }
uint64_t size() const {
uint64_t rHigh = cast<ConstantInt>(High)->getSExtValue();
uint64_t rLow = cast<ConstantInt>(Low)->getSExtValue();
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 SDLowering 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;
std::vector<std::pair<MachineInstr*, unsigned> > PHINodesToUpdate;
// 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;
SelectionDAGLowering(SelectionDAG &dag, TargetLowering &tli,
FunctionLoweringInfo &funcinfo,
CodeGenOpt::Level ol)
: CurDebugLoc(DebugLoc::getUnknownLoc()),
TLI(tli), DAG(dag), FuncInfo(funcinfo), OptLevel(ol) {
}
void init(GCFunctionInfo *gfi, AliasAnalysis &aa);
/// clear - Clear out the curret SelectionDAG and the associated
/// state and prepare this SelectionDAGLowering 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; }
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 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);
void visitSub(User &I);
void visitMul(User &I);
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);
void visitVICmp(User &I);
void visitVFCmp(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 visitMalloc(MallocInst &I);
void visitFree(FreeInst &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);
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) {
assert(0 && "UserOp1 should not exist at instruction selection time!");
abort();
}
void visitUserOp2(Instruction &I) {
assert(0 && "UserOp2 should not exist at instruction selection time!");
abort();
}
const char *implVisitBinaryAtomic(CallInst& I, ISD::NodeType Op);
const char *implVisitAluOverflow(CallInst &I, ISD::NodeType Op);
};
/// AddCatchInfo - Extract the personality and type infos from an eh.selector
/// call, and add them to the specified machine basic block.
void AddCatchInfo(CallInst &I, MachineModuleInfo *MMI,
MachineBasicBlock *MBB);
} // end namespace llvm
#endif
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