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