Rename SelectionDAGLowering to SelectionDAGBuilder, and rename
SelectionDAGBuild.cpp to SelectionDAGBuilder.cpp.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89681 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
new file mode 100644
index 0000000..244f9b5
--- /dev/null
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.h
@@ -0,0 +1,487 @@
+//===-- 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;
+
+  /// 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) { }
+    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()), 
+      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; }
+
+  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);
+  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