1 //===-- User.cpp - Implement the User class -------------------------------===//
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 #include "llvm/IR/User.h"
11 #include "llvm/IR/Constant.h"
12 #include "llvm/IR/GlobalValue.h"
13 #include "llvm/IR/Operator.h"
18 //===----------------------------------------------------------------------===//
20 //===----------------------------------------------------------------------===//
22 void User::anchor() {}
24 void User::replaceUsesOfWith(Value *From, Value *To) {
25 if (From == To) return; // Duh what?
27 assert((!isa<Constant>(this) || isa<GlobalValue>(this)) &&
28 "Cannot call User::replaceUsesOfWith on a constant!");
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...
39 //===----------------------------------------------------------------------===//
40 // User allocHungoffUses Implementation
41 //===----------------------------------------------------------------------===//
43 void User::allocHungoffUses(unsigned N, bool IsPhi) {
44 assert(HasHungOffUses && "alloc must have hung off uses");
46 static_assert(AlignOf<Use>::Alignment >= AlignOf<Use::UserRef>::Alignment,
47 "Alignment sufficient for hung-off-uses pieces");
48 static_assert(AlignOf<Use::UserRef>::Alignment >= AlignOf<BasicBlock *>::Alignment,
49 "Alignment sufficient for hung-off-uses pieces");
51 // Allocate the array of Uses, followed by a pointer (with bottom bit set) to
53 size_t size = N * sizeof(Use) + sizeof(Use::UserRef);
55 size += N * sizeof(BasicBlock *);
56 Use *Begin = static_cast<Use*>(::operator new(size));
58 (void) new(End) Use::UserRef(const_cast<User*>(this), 1);
59 setOperandList(Use::initTags(Begin, End));
62 void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) {
63 assert(HasHungOffUses && "realloc must have hung off uses");
65 unsigned OldNumUses = getNumOperands();
67 // We don't support shrinking the number of uses. We wouldn't have enough
68 // space to copy the old uses in to the new space.
69 assert(NewNumUses > OldNumUses && "realloc must grow num uses");
71 Use *OldOps = getOperandList();
72 allocHungoffUses(NewNumUses, IsPhi);
73 Use *NewOps = getOperandList();
75 // Now copy from the old operands list to the new one.
76 std::copy(OldOps, OldOps + OldNumUses, NewOps);
78 // If this is a Phi, then we need to copy the BB pointers too.
81 reinterpret_cast<char *>(OldOps + OldNumUses) + sizeof(Use::UserRef);
83 reinterpret_cast<char *>(NewOps + NewNumUses) + sizeof(Use::UserRef);
84 std::copy(OldPtr, OldPtr + (OldNumUses * sizeof(BasicBlock *)), NewPtr);
86 Use::zap(OldOps, OldOps + OldNumUses, true);
89 //===----------------------------------------------------------------------===//
90 // User operator new Implementations
91 //===----------------------------------------------------------------------===//
93 void *User::operator new(size_t Size, unsigned Us) {
94 assert(Us < (1u << NumUserOperandsBits) && "Too many operands");
95 void *Storage = ::operator new(Size + sizeof(Use) * Us);
96 Use *Start = static_cast<Use*>(Storage);
97 Use *End = Start + Us;
98 User *Obj = reinterpret_cast<User*>(End);
99 Obj->NumUserOperands = Us;
100 Obj->HasHungOffUses = false;
101 Use::initTags(Start, End);
105 void *User::operator new(size_t Size) {
106 // Allocate space for a single Use*
107 void *Storage = ::operator new(Size + sizeof(Use *));
108 Use **HungOffOperandList = static_cast<Use **>(Storage);
109 User *Obj = reinterpret_cast<User *>(HungOffOperandList + 1);
110 Obj->NumUserOperands = 0;
111 Obj->HasHungOffUses = true;
112 *HungOffOperandList = nullptr;
116 //===----------------------------------------------------------------------===//
117 // User operator delete Implementation
118 //===----------------------------------------------------------------------===//
120 void User::operator delete(void *Usr) {
121 // Hung off uses use a single Use* before the User, while other subclasses
122 // use a Use[] allocated prior to the user.
123 User *Obj = static_cast<User *>(Usr);
124 if (Obj->HasHungOffUses) {
125 Use **HungOffOperandList = static_cast<Use **>(Usr) - 1;
126 // drop the hung off uses.
127 Use::zap(*HungOffOperandList, *HungOffOperandList + Obj->NumUserOperands,
129 ::operator delete(HungOffOperandList);
131 Use *Storage = static_cast<Use *>(Usr) - Obj->NumUserOperands;
132 Use::zap(Storage, Storage + Obj->NumUserOperands,
134 ::operator delete(Storage);
138 //===----------------------------------------------------------------------===//
140 //===----------------------------------------------------------------------===//
142 Operator::~Operator() {
143 llvm_unreachable("should never destroy an Operator");
146 } // End llvm namespace