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");
45 // Allocate the array of Uses, followed by a pointer (with bottom bit set) to
47 size_t size = N * sizeof(Use) + sizeof(Use::UserRef);
49 size += N * sizeof(BasicBlock *);
50 Use *Begin = static_cast<Use*>(::operator new(size));
52 (void) new(End) Use::UserRef(const_cast<User*>(this), 1);
53 setOperandList(Use::initTags(Begin, End));
56 void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) {
57 assert(HasHungOffUses && "realloc must have hung off uses");
59 unsigned OldNumUses = getNumOperands();
61 // We don't support shrinking the number of uses. We wouldn't have enough
62 // space to copy the old uses in to the new space.
63 assert(NewNumUses > OldNumUses && "realloc must grow num uses");
65 Use *OldOps = getOperandList();
66 allocHungoffUses(NewNumUses, IsPhi);
67 Use *NewOps = getOperandList();
69 // Now copy from the old operands list to the new one.
70 std::copy(OldOps, OldOps + OldNumUses, NewOps);
72 // If this is a Phi, then we need to copy the BB pointers too.
75 reinterpret_cast<char *>(OldOps + OldNumUses) + sizeof(Use::UserRef);
77 reinterpret_cast<char *>(NewOps + NewNumUses) + sizeof(Use::UserRef);
78 std::copy(OldPtr, OldPtr + (OldNumUses * sizeof(BasicBlock *)), NewPtr);
80 Use::zap(OldOps, OldOps + OldNumUses, true);
83 //===----------------------------------------------------------------------===//
84 // User operator new Implementations
85 //===----------------------------------------------------------------------===//
87 void *User::operator new(size_t Size, unsigned Us) {
88 assert(Us < (1u << NumUserOperandsBits) && "Too many operands");
89 void *Storage = ::operator new(Size + sizeof(Use) * Us);
90 Use *Start = static_cast<Use*>(Storage);
91 Use *End = Start + Us;
92 User *Obj = reinterpret_cast<User*>(End);
93 Obj->NumUserOperands = Us;
94 Obj->HasHungOffUses = false;
95 Use::initTags(Start, End);
99 void *User::operator new(size_t Size) {
100 // Allocate space for a single Use*
101 void *Storage = ::operator new(Size + sizeof(Use *));
102 Use **HungOffOperandList = static_cast<Use **>(Storage);
103 User *Obj = reinterpret_cast<User *>(HungOffOperandList + 1);
104 Obj->NumUserOperands = 0;
105 Obj->HasHungOffUses = true;
106 *HungOffOperandList = nullptr;
110 //===----------------------------------------------------------------------===//
111 // User operator delete Implementation
112 //===----------------------------------------------------------------------===//
114 void User::operator delete(void *Usr) {
115 // Hung off uses use a single Use* before the User, while other subclasses
116 // use a Use[] allocated prior to the user.
117 User *Obj = static_cast<User *>(Usr);
118 if (Obj->HasHungOffUses) {
119 Use **HungOffOperandList = static_cast<Use **>(Usr) - 1;
120 // drop the hung off uses.
121 Use::zap(*HungOffOperandList, *HungOffOperandList + Obj->NumUserOperands,
123 ::operator delete(HungOffOperandList);
125 Use *Storage = static_cast<Use *>(Usr) - Obj->NumUserOperands;
126 Use::zap(Storage, Storage + Obj->NumUserOperands,
128 ::operator delete(Storage);
132 //===----------------------------------------------------------------------===//
134 //===----------------------------------------------------------------------===//
136 Operator::~Operator() {
137 llvm_unreachable("should never destroy an Operator");
140 } // End llvm namespace