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
14 namespace 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 //
replaceUsesOfWith(Value * From,Value * To)23 void 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
allocHungoffUses(unsigned N) const42 Use *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
operator new(size_t s,unsigned Us)56 void *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
operator delete(void * Usr)71 void 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