llvm-6502/lib/CodeGen/SelectionDAG/SelectionDAGBuild.h
Dan Gohman 98ca4f2a32 Major calling convention code refactoring.
Instead of awkwardly encoding calling-convention information with ISD::CALL,
ISD::FORMAL_ARGUMENTS, ISD::RET, and ISD::ARG_FLAGS nodes, TargetLowering
provides three virtual functions for targets to override:
LowerFormalArguments, LowerCall, and LowerRet, which replace the custom
lowering done on the special nodes. They provide the same information, but
in a more immediately usable format.

This also reworks much of the target-independent tail call logic. The
decision of whether or not to perform a tail call is now cleanly split
between target-independent portions, and the target dependent portion
in IsEligibleForTailCallOptimization.

This also synchronizes all in-tree targets, to help enable future
refactoring and feature work.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78142 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-05 01:29:28 +00:00

568 lines
19 KiB
C++

//===-- 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/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 "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 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;
/// 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;
SelectionDAGLowering(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 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) { 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 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) {
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);
};
/// 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