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
15namespace llvm {
16
17//===----------------------------------------------------------------------===//
18//                                 User Class
19//===----------------------------------------------------------------------===//
20
21void User::anchor() {}
22
23// replaceUsesOfWith - Replaces all references to the "From" definition with
24// references to the "To" definition.
25//
26void User::replaceUsesOfWith(Value *From, Value *To) {
27  if (From == To) return;   // Duh what?
28
29  assert((!isa<Constant>(this) || isa<GlobalValue>(this)) &&
30         "Cannot call User::replaceUsesOfWith on a constant!");
31
32  for (unsigned i = 0, E = getNumOperands(); i != E; ++i)
33    if (getOperand(i) == From) {  // Is This operand is pointing to oldval?
34      // The side effects of this setOperand call include linking to
35      // "To", adding "this" to the uses list of To, and
36      // most importantly, removing "this" from the use list of "From".
37      setOperand(i, To); // Fix it now...
38    }
39}
40
41//===----------------------------------------------------------------------===//
42//                         User allocHungoffUses Implementation
43//===----------------------------------------------------------------------===//
44
45Use *User::allocHungoffUses(unsigned N) const {
46  // Allocate the array of Uses, followed by a pointer (with bottom bit set) to
47  // the User.
48  size_t size = N * sizeof(Use) + sizeof(Use::UserRef);
49  Use *Begin = static_cast<Use*>(::operator new(size));
50  Use *End = Begin + N;
51  (void) new(End) Use::UserRef(const_cast<User*>(this), 1);
52  return Use::initTags(Begin, End);
53}
54
55//===----------------------------------------------------------------------===//
56//                         User operator new Implementations
57//===----------------------------------------------------------------------===//
58
59void *User::operator new(size_t s, unsigned Us) {
60  void *Storage = ::operator new(s + sizeof(Use) * Us);
61  Use *Start = static_cast<Use*>(Storage);
62  Use *End = Start + Us;
63  User *Obj = reinterpret_cast<User*>(End);
64  Obj->OperandList = Start;
65  Obj->NumOperands = Us;
66  Use::initTags(Start, End);
67  return Obj;
68}
69
70//===----------------------------------------------------------------------===//
71//                         User operator delete Implementation
72//===----------------------------------------------------------------------===//
73
74void User::operator delete(void *Usr) {
75  User *Start = static_cast<User*>(Usr);
76  Use *Storage = static_cast<Use*>(Usr) - Start->NumOperands;
77  // If there were hung-off uses, they will have been freed already and
78  // NumOperands reset to 0, so here we just free the User itself.
79  ::operator delete(Storage);
80}
81
82//===----------------------------------------------------------------------===//
83//                             Operator Class
84//===----------------------------------------------------------------------===//
85
86Operator::~Operator() {
87  llvm_unreachable("should never destroy an Operator");
88}
89
90} // End llvm namespace
91