1 //===-- FunctionLoweringInfo.h - Lower functions from LLVM IR to CodeGen --===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This implements routines for translating functions from LLVM IR into
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_CODEGEN_FUNCTIONLOWERINGINFO_H
16 #define LLVM_CODEGEN_FUNCTIONLOWERINGINFO_H
18 #include "llvm/ADT/APInt.h"
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/ADT/IndexedMap.h"
21 #include "llvm/ADT/Optional.h"
22 #include "llvm/ADT/SmallPtrSet.h"
23 #include "llvm/ADT/SmallVector.h"
24 #include "llvm/CodeGen/ISDOpcodes.h"
25 #include "llvm/CodeGen/MachineBasicBlock.h"
26 #include "llvm/IR/InlineAsm.h"
27 #include "llvm/IR/Instructions.h"
28 #include "llvm/Target/TargetRegisterInfo.h"
35 class BranchProbabilityInfo;
41 class MachineBasicBlock;
42 class MachineFunction;
43 class MachineModuleInfo;
44 class MachineRegisterInfo;
50 //===--------------------------------------------------------------------===//
51 /// FunctionLoweringInfo - This contains information that is global to a
52 /// function that is used when lowering a region of the function.
54 class FunctionLoweringInfo {
58 const TargetLowering *TLI;
59 MachineRegisterInfo *RegInfo;
60 BranchProbabilityInfo *BPI;
61 /// CanLowerReturn - true iff the function's return value can be lowered to
65 /// DemoteRegister - if CanLowerReturn is false, DemoteRegister is a vreg
66 /// allocated to hold a pointer to the hidden sret parameter.
67 unsigned DemoteRegister;
69 /// MBBMap - A mapping from LLVM basic blocks to their machine code entry.
70 DenseMap<const BasicBlock*, MachineBasicBlock *> MBBMap;
72 /// ValueMap - Since we emit code for the function a basic block at a time,
73 /// we must remember which virtual registers hold the values for
74 /// cross-basic-block values.
75 DenseMap<const Value *, unsigned> ValueMap;
77 /// Track virtual registers created for exception pointers.
78 DenseMap<const Value *, unsigned> CatchPadExceptionPointers;
80 // Keep track of frame indices allocated for statepoints as they could be used
81 // across basic block boundaries.
82 // Key of the map is statepoint instruction, value is a map from spilled
83 // llvm Value to the optional stack stack slot index.
84 // If optional is unspecified it means that we have visited this value
85 // but didn't spill it.
86 typedef DenseMap<const Value*, Optional<int>> StatepointSpilledValueMapTy;
87 DenseMap<const Instruction*, StatepointSpilledValueMapTy>
88 StatepointRelocatedValues;
90 /// StaticAllocaMap - Keep track of frame indices for fixed sized allocas in
91 /// the entry block. This allows the allocas to be efficiently referenced
92 /// anywhere in the function.
93 DenseMap<const AllocaInst*, int> StaticAllocaMap;
95 /// ByValArgFrameIndexMap - Keep track of frame indices for byval arguments.
96 DenseMap<const Argument*, int> ByValArgFrameIndexMap;
98 /// ArgDbgValues - A list of DBG_VALUE instructions created during isel for
99 /// function arguments that are inserted after scheduling is completed.
100 SmallVector<MachineInstr*, 8> ArgDbgValues;
102 /// RegFixups - Registers which need to be replaced after isel is done.
103 DenseMap<unsigned, unsigned> RegFixups;
105 /// StatepointStackSlots - A list of temporary stack slots (frame indices)
106 /// used to spill values at a statepoint. We store them here to enable
107 /// reuse of the same stack slots across different statepoints in different
109 SmallVector<unsigned, 50> StatepointStackSlots;
111 /// MBB - The current block.
112 MachineBasicBlock *MBB;
114 /// MBB - The current insert position inside the current block.
115 MachineBasicBlock::iterator InsertPt;
118 SmallPtrSet<const Instruction *, 8> CatchInfoLost;
119 SmallPtrSet<const Instruction *, 8> CatchInfoFound;
123 unsigned NumSignBits : 31;
125 APInt KnownOne, KnownZero;
126 LiveOutInfo() : NumSignBits(0), IsValid(true), KnownOne(1, 0),
130 /// Record the preferred extend type (ISD::SIGN_EXTEND or ISD::ZERO_EXTEND)
132 DenseMap<const Value *, ISD::NodeType> PreferredExtendType;
134 /// VisitedBBs - The set of basic blocks visited thus far by instruction
136 SmallPtrSet<const BasicBlock*, 4> VisitedBBs;
138 /// PHINodesToUpdate - A list of phi instructions whose operand list will
139 /// be updated after processing the current basic block.
140 /// TODO: This isn't per-function state, it's per-basic-block state. But
141 /// there's no other convenient place for it to live right now.
142 std::vector<std::pair<MachineInstr*, unsigned> > PHINodesToUpdate;
143 unsigned OrigNumPHINodesToUpdate;
145 /// If the current MBB is a landing pad, the exception pointer and exception
146 /// selector registers are copied into these virtual registers by
147 /// SelectionDAGISel::PrepareEHLandingPad().
148 unsigned ExceptionPointerVirtReg, ExceptionSelectorVirtReg;
150 /// set - Initialize this FunctionLoweringInfo with the given Function
151 /// and its associated MachineFunction.
153 void set(const Function &Fn, MachineFunction &MF, SelectionDAG *DAG);
155 /// clear - Clear out all the function-specific state. This returns this
156 /// FunctionLoweringInfo to an empty state, ready to be used for a
157 /// different function.
160 /// isExportedInst - Return true if the specified value is an instruction
161 /// exported from its block.
162 bool isExportedInst(const Value *V) {
163 return ValueMap.count(V);
166 unsigned CreateReg(MVT VT);
168 unsigned CreateRegs(Type *Ty);
170 unsigned InitializeRegForValue(const Value *V) {
171 // Tokens never live in vregs.
172 if (V->getType()->isTokenTy())
174 unsigned &R = ValueMap[V];
175 assert(R == 0 && "Already initialized this value register!");
176 return R = CreateRegs(V->getType());
179 /// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the
180 /// register is a PHI destination and the PHI's LiveOutInfo is not valid.
181 const LiveOutInfo *GetLiveOutRegInfo(unsigned Reg) {
182 if (!LiveOutRegInfo.inBounds(Reg))
185 const LiveOutInfo *LOI = &LiveOutRegInfo[Reg];
192 /// GetLiveOutRegInfo - Gets LiveOutInfo for a register, returning NULL if the
193 /// register is a PHI destination and the PHI's LiveOutInfo is not valid. If
194 /// the register's LiveOutInfo is for a smaller bit width, it is extended to
195 /// the larger bit width by zero extension. The bit width must be no smaller
196 /// than the LiveOutInfo's existing bit width.
197 const LiveOutInfo *GetLiveOutRegInfo(unsigned Reg, unsigned BitWidth);
199 /// AddLiveOutRegInfo - Adds LiveOutInfo for a register.
200 void AddLiveOutRegInfo(unsigned Reg, unsigned NumSignBits,
201 const APInt &KnownZero, const APInt &KnownOne) {
202 // Only install this information if it tells us something.
203 if (NumSignBits == 1 && KnownZero == 0 && KnownOne == 0)
206 LiveOutRegInfo.grow(Reg);
207 LiveOutInfo &LOI = LiveOutRegInfo[Reg];
208 LOI.NumSignBits = NumSignBits;
209 LOI.KnownOne = KnownOne;
210 LOI.KnownZero = KnownZero;
213 /// ComputePHILiveOutRegInfo - Compute LiveOutInfo for a PHI's destination
214 /// register based on the LiveOutInfo of its operands.
215 void ComputePHILiveOutRegInfo(const PHINode*);
217 /// InvalidatePHILiveOutRegInfo - Invalidates a PHI's LiveOutInfo, to be
218 /// called when a block is visited before all of its predecessors.
219 void InvalidatePHILiveOutRegInfo(const PHINode *PN) {
220 // PHIs with no uses have no ValueMap entry.
221 DenseMap<const Value*, unsigned>::const_iterator It = ValueMap.find(PN);
222 if (It == ValueMap.end())
225 unsigned Reg = It->second;
229 LiveOutRegInfo.grow(Reg);
230 LiveOutRegInfo[Reg].IsValid = false;
233 /// setArgumentFrameIndex - Record frame index for the byval
235 void setArgumentFrameIndex(const Argument *A, int FI);
237 /// getArgumentFrameIndex - Get frame index for the byval argument.
238 int getArgumentFrameIndex(const Argument *A);
240 unsigned getCatchPadExceptionPointerVReg(const Value *CPI,
241 const TargetRegisterClass *RC);
244 void addSEHHandlersForLPads(ArrayRef<const LandingPadInst *> LPads);
246 /// LiveOutRegInfo - Information about live out vregs.
247 IndexedMap<LiveOutInfo, VirtReg2IndexFunctor> LiveOutRegInfo;
250 /// ComputeUsesVAFloatArgument - Determine if any floating-point values are
251 /// being passed to this variadic function, and set the MachineModuleInfo's
252 /// usesVAFloatArgument flag if so. This flag is used to emit an undefined
253 /// reference to _fltused on Windows, which will link in MSVCRT's
254 /// floating-point support.
255 void ComputeUsesVAFloatArgument(const CallInst &I, MachineModuleInfo *MMI);
257 /// AddLandingPadInfo - Extract the exception handling information from the
258 /// landingpad instruction and add them to the specified machine module info.
259 void AddLandingPadInfo(const LandingPadInst &I, MachineModuleInfo &MMI,
260 MachineBasicBlock *MBB);
262 } // end namespace llvm