1 //===-- User.cpp - Implement the User class -------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #include "llvm/IR/User.h" 11 #include "llvm/IR/Constant.h" 12 #include "llvm/IR/GlobalValue.h" 13 #include "llvm/IR/Operator.h" 14 15 namespace llvm { 16 class BasicBlock; 17 18 //===----------------------------------------------------------------------===// 19 // User Class 20 //===----------------------------------------------------------------------===// 21 22 void User::anchor() {} 23 24 void User::replaceUsesOfWith(Value *From, Value *To) { 25 if (From == To) return; // Duh what? 26 27 assert((!isa<Constant>(this) || isa<GlobalValue>(this)) && 28 "Cannot call User::replaceUsesOfWith on a constant!"); 29 30 for (unsigned i = 0, E = getNumOperands(); i != E; ++i) 31 if (getOperand(i) == From) { // Is This operand is pointing to oldval? 32 // The side effects of this setOperand call include linking to 33 // "To", adding "this" to the uses list of To, and 34 // most importantly, removing "this" from the use list of "From". 35 setOperand(i, To); // Fix it now... 36 } 37 } 38 39 //===----------------------------------------------------------------------===// 40 // User allocHungoffUses Implementation 41 //===----------------------------------------------------------------------===// 42 43 void User::allocHungoffUses(unsigned N, bool IsPhi) { 44 assert(HasHungOffUses && "alloc must have hung off uses"); 45 46 static_assert(AlignOf<Use>::Alignment >= AlignOf<Use::UserRef>::Alignment, 47 "Alignment is insufficient for 'hung-off-uses' pieces"); 48 static_assert(AlignOf<Use::UserRef>::Alignment >= 49 AlignOf<BasicBlock *>::Alignment, 50 "Alignment is insufficient for 'hung-off-uses' pieces"); 51 52 // Allocate the array of Uses, followed by a pointer (with bottom bit set) to 53 // the User. 54 size_t size = N * sizeof(Use) + sizeof(Use::UserRef); 55 if (IsPhi) 56 size += N * sizeof(BasicBlock *); 57 Use *Begin = static_cast<Use*>(::operator new(size)); 58 Use *End = Begin + N; 59 (void) new(End) Use::UserRef(const_cast<User*>(this), 1); 60 setOperandList(Use::initTags(Begin, End)); 61 } 62 63 void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) { 64 assert(HasHungOffUses && "realloc must have hung off uses"); 65 66 unsigned OldNumUses = getNumOperands(); 67 68 // We don't support shrinking the number of uses. We wouldn't have enough 69 // space to copy the old uses in to the new space. 70 assert(NewNumUses > OldNumUses && "realloc must grow num uses"); 71 72 Use *OldOps = getOperandList(); 73 allocHungoffUses(NewNumUses, IsPhi); 74 Use *NewOps = getOperandList(); 75 76 // Now copy from the old operands list to the new one. 77 std::copy(OldOps, OldOps + OldNumUses, NewOps); 78 79 // If this is a Phi, then we need to copy the BB pointers too. 80 if (IsPhi) { 81 auto *OldPtr = 82 reinterpret_cast<char *>(OldOps + OldNumUses) + sizeof(Use::UserRef); 83 auto *NewPtr = 84 reinterpret_cast<char *>(NewOps + NewNumUses) + sizeof(Use::UserRef); 85 std::copy(OldPtr, OldPtr + (OldNumUses * sizeof(BasicBlock *)), NewPtr); 86 } 87 Use::zap(OldOps, OldOps + OldNumUses, true); 88 } 89 90 //===----------------------------------------------------------------------===// 91 // User operator new Implementations 92 //===----------------------------------------------------------------------===// 93 94 void *User::operator new(size_t Size, unsigned Us) { 95 assert(Us < (1u << NumUserOperandsBits) && "Too many operands"); 96 void *Storage = ::operator new(Size + sizeof(Use) * Us); 97 Use *Start = static_cast<Use*>(Storage); 98 Use *End = Start + Us; 99 User *Obj = reinterpret_cast<User*>(End); 100 Obj->NumUserOperands = Us; 101 Obj->HasHungOffUses = false; 102 Use::initTags(Start, End); 103 return Obj; 104 } 105 106 void *User::operator new(size_t Size) { 107 // Allocate space for a single Use* 108 void *Storage = ::operator new(Size + sizeof(Use *)); 109 Use **HungOffOperandList = static_cast<Use **>(Storage); 110 User *Obj = reinterpret_cast<User *>(HungOffOperandList + 1); 111 Obj->NumUserOperands = 0; 112 Obj->HasHungOffUses = true; 113 *HungOffOperandList = nullptr; 114 return Obj; 115 } 116 117 //===----------------------------------------------------------------------===// 118 // User operator delete Implementation 119 //===----------------------------------------------------------------------===// 120 121 void User::operator delete(void *Usr) { 122 // Hung off uses use a single Use* before the User, while other subclasses 123 // use a Use[] allocated prior to the user. 124 User *Obj = static_cast<User *>(Usr); 125 if (Obj->HasHungOffUses) { 126 Use **HungOffOperandList = static_cast<Use **>(Usr) - 1; 127 // drop the hung off uses. 128 Use::zap(*HungOffOperandList, *HungOffOperandList + Obj->NumUserOperands, 129 /* Delete */ true); 130 ::operator delete(HungOffOperandList); 131 } else { 132 Use *Storage = static_cast<Use *>(Usr) - Obj->NumUserOperands; 133 Use::zap(Storage, Storage + Obj->NumUserOperands, 134 /* Delete */ false); 135 ::operator delete(Storage); 136 } 137 } 138 139 //===----------------------------------------------------------------------===// 140 // Operator Class 141 //===----------------------------------------------------------------------===// 142 143 Operator::~Operator() { 144 llvm_unreachable("should never destroy an Operator"); 145 } 146 147 } // End llvm namespace 148