1 //===- SwiftErrorValueTracking.h - Track swifterror VReg vals --*- C++ -*--===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This implements a limited mem2reg-like analysis to promote uses of function 10 // arguments and allocas marked with swiftalloc from memory into virtual 11 // registers tracked by this class. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #ifndef LLVM_CODEGEN_SWIFTERRORVALUETRACKING_H 16 #define LLVM_CODEGEN_SWIFTERRORVALUETRACKING_H 17 18 #include "llvm/ADT/DenseMap.h" 19 #include "llvm/ADT/SmallVector.h" 20 #include "llvm/CodeGen/Register.h" 21 #include "llvm/IR/BasicBlock.h" 22 #include "llvm/IR/DebugLoc.h" 23 #include <utility> 24 25 26 namespace llvm { 27 class Function; 28 class MachineBasicBlock; 29 class MachineFunction; 30 class MachineInstr; 31 class TargetInstrInfo; 32 class TargetLowering; 33 34 class SwiftErrorValueTracking { 35 // Some useful objects to reduce the number of function arguments needed. 36 MachineFunction *MF; 37 const Function *Fn; 38 const TargetLowering *TLI; 39 const TargetInstrInfo *TII; 40 41 /// A map from swifterror value in a basic block to the virtual register it is 42 /// currently represented by. 43 DenseMap<std::pair<const MachineBasicBlock *, const Value *>, Register> 44 VRegDefMap; 45 46 /// A list of upward exposed vreg uses that need to be satisfied by either a 47 /// copy def or a phi node at the beginning of the basic block representing 48 /// the predecessor(s) swifterror value. 49 DenseMap<std::pair<const MachineBasicBlock *, const Value *>, Register> 50 VRegUpwardsUse; 51 52 /// A map from instructions that define/use a swifterror value to the virtual 53 /// register that represents that def/use. 54 llvm::DenseMap<PointerIntPair<const Instruction *, 1, bool>, Register> 55 VRegDefUses; 56 57 /// The swifterror argument of the current function. 58 const Value *SwiftErrorArg; 59 60 using SwiftErrorValues = SmallVector<const Value*, 1>; 61 /// A function can only have a single swifterror argument. And if it does 62 /// have a swifterror argument, it must be the first entry in 63 /// SwiftErrorVals. 64 SwiftErrorValues SwiftErrorVals; 65 66 public: 67 /// Initialize data structures for specified new function. 68 void setFunction(MachineFunction &MF); 69 70 /// Get the (unique) function argument that was marked swifterror, or nullptr 71 /// if this function has no swifterror args. 72 const Value *getFunctionArg() const { 73 return SwiftErrorArg; 74 } 75 76 /// Get or create the swifterror value virtual register in 77 /// VRegDefMap for this basic block. 78 Register getOrCreateVReg(const MachineBasicBlock *, const Value *); 79 80 /// Set the swifterror virtual register in the VRegDefMap for this 81 /// basic block. 82 void setCurrentVReg(const MachineBasicBlock *MBB, const Value *, Register); 83 84 /// Get or create the swifterror value virtual register for a def of a 85 /// swifterror by an instruction. 86 Register getOrCreateVRegDefAt(const Instruction *, const MachineBasicBlock *, 87 const Value *); 88 89 /// Get or create the swifterror value virtual register for a use of a 90 /// swifterror by an instruction. 91 Register getOrCreateVRegUseAt(const Instruction *, const MachineBasicBlock *, 92 const Value *); 93 94 /// Create initial definitions of swifterror values in the entry block of the 95 /// current function. 96 bool createEntriesInEntryBlock(DebugLoc DbgLoc); 97 98 /// Propagate assigned swifterror vregs through a function, synthesizing PHI 99 /// nodes when needed to maintain consistency. 100 void propagateVRegs(); 101 102 void preassignVRegs(MachineBasicBlock *MBB, BasicBlock::const_iterator Begin, 103 BasicBlock::const_iterator End); 104 }; 105 106 } 107 108 #endif 109