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/Constant.h"
11#include "llvm/GlobalValue.h"
12#include "llvm/User.h"
13
14namespace llvm {
15
16//===----------------------------------------------------------------------===//
17//                                 User Class
18//===----------------------------------------------------------------------===//
19
20void User::anchor() {}
21
22// replaceUsesOfWith - Replaces all references to the "From" definition with
23// references to the "To" definition.
24//
25void User::replaceUsesOfWith(Value *From, Value *To) {
26  if (From == To) return;   // Duh what?
27
28  assert((!isa<Constant>(this) || isa<GlobalValue>(this)) &&
29         "Cannot call User::replaceUsesOfWith on a constant!");
30
31  for (unsigned i = 0, E = getNumOperands(); i != E; ++i)
32    if (getOperand(i) == From) {  // Is This operand is pointing to oldval?
33      // The side effects of this setOperand call include linking to
34      // "To", adding "this" to the uses list of To, and
35      // most importantly, removing "this" from the use list of "From".
36      setOperand(i, To); // Fix it now...
37    }
38}
39
40//===----------------------------------------------------------------------===//
41//                         User allocHungoffUses Implementation
42//===----------------------------------------------------------------------===//
43
44Use *User::allocHungoffUses(unsigned N) const {
45  // Allocate the array of Uses, followed by a pointer (with bottom bit set) to
46  // the User.
47  size_t size = N * sizeof(Use) + sizeof(Use::UserRef);
48  Use *Begin = static_cast<Use*>(::operator new(size));
49  Use *End = Begin + N;
50  (void) new(End) Use::UserRef(const_cast<User*>(this), 1);
51  return Use::initTags(Begin, End);
52}
53
54//===----------------------------------------------------------------------===//
55//                         User operator new Implementations
56//===----------------------------------------------------------------------===//
57
58void *User::operator new(size_t s, unsigned Us) {
59  void *Storage = ::operator new(s + sizeof(Use) * Us);
60  Use *Start = static_cast<Use*>(Storage);
61  Use *End = Start + Us;
62  User *Obj = reinterpret_cast<User*>(End);
63  Obj->OperandList = Start;
64  Obj->NumOperands = Us;
65  Use::initTags(Start, End);
66  return Obj;
67}
68
69//===----------------------------------------------------------------------===//
70//                         User operator delete Implementation
71//===----------------------------------------------------------------------===//
72
73void User::operator delete(void *Usr) {
74  User *Start = static_cast<User*>(Usr);
75  Use *Storage = static_cast<Use*>(Usr) - Start->NumOperands;
76  // If there were hung-off uses, they will have been freed already and
77  // NumOperands reset to 0, so here we just free the User itself.
78  ::operator delete(Storage);
79}
80
81} // End llvm namespace
82