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");
46 static_assert(alignof(Use) >= alignof(Use::UserRef),
47 "Alignment is insufficient for 'hung-off-uses' pieces");
48 static_assert(alignof(Use::UserRef) >= alignof(BasicBlock *),
49 "Alignment is insufficient for 'hung-off-uses' pieces");
51 // Allocate the array of Uses, followed by a pointer (with bottom bit set) to
53 size_t size = N * sizeof(Use) + sizeof(Use::UserRef);
55 size += N * sizeof(BasicBlock *);
56 Use *Begin = static_cast<Use*>(::operator new(size));
58 (void) new(End) Use::UserRef(const_cast<User*>(this), 1);
59 setOperandList(Use::initTags(Begin, End));
62 void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) {
63 assert(HasHungOffUses && "realloc must have hung off uses");
65 unsigned OldNumUses = getNumOperands();
67 // We don't support shrinking the number of uses. We wouldn't have enough
68 // space to copy the old uses in to the new space.
69 assert(NewNumUses > OldNumUses && "realloc must grow num uses");
71 Use *OldOps = getOperandList();
72 allocHungoffUses(NewNumUses, IsPhi);
73 Use *NewOps = getOperandList();
75 // Now copy from the old operands list to the new one.
76 std::copy(OldOps, OldOps + OldNumUses, NewOps);
78 // If this is a Phi, then we need to copy the BB pointers too.
81 reinterpret_cast<char *>(OldOps + OldNumUses) + sizeof(Use::UserRef);
83 reinterpret_cast<char *>(NewOps + NewNumUses) + sizeof(Use::UserRef);
84 std::copy(OldPtr, OldPtr + (OldNumUses * sizeof(BasicBlock *)), NewPtr);
86 Use::zap(OldOps, OldOps + OldNumUses, true);
90 // This is a private struct used by `User` to track the co-allocated descriptor
92 struct DescriptorInfo {
96 ArrayRef<const uint8_t> User::getDescriptor() const {
97 auto MutableARef = const_cast<User *>(this)->getDescriptor();
98 return {MutableARef.begin(), MutableARef.end()};
101 MutableArrayRef<uint8_t> User::getDescriptor() {
102 assert(HasDescriptor && "Don't call otherwise!");
103 assert(!HasHungOffUses && "Invariant!");
105 auto *DI = reinterpret_cast<DescriptorInfo *>(getIntrusiveOperands()) - 1;
106 assert(DI->SizeInBytes != 0 && "Should not have had a descriptor otherwise!");
108 return MutableArrayRef<uint8_t>(
109 reinterpret_cast<uint8_t *>(DI) - DI->SizeInBytes, DI->SizeInBytes);
112 //===----------------------------------------------------------------------===//
113 // User operator new Implementations
114 //===----------------------------------------------------------------------===//
116 void *User::allocateFixedOperandUser(size_t Size, unsigned Us,
117 unsigned DescBytes) {
118 assert(Us < (1u << NumUserOperandsBits) && "Too many operands");
120 static_assert(sizeof(DescriptorInfo) % sizeof(void *) == 0, "Required below");
122 unsigned DescBytesToAllocate =
123 DescBytes == 0 ? 0 : (DescBytes + sizeof(DescriptorInfo));
124 assert(DescBytesToAllocate % sizeof(void *) == 0 &&
125 "We need this to satisfy alignment constraints for Uses");
127 uint8_t *Storage = static_cast<uint8_t *>(
128 ::operator new(Size + sizeof(Use) * Us + DescBytesToAllocate));
129 Use *Start = reinterpret_cast<Use *>(Storage + DescBytesToAllocate);
130 Use *End = Start + Us;
131 User *Obj = reinterpret_cast<User*>(End);
132 Obj->NumUserOperands = Us;
133 Obj->HasHungOffUses = false;
134 Obj->HasDescriptor = DescBytes != 0;
135 Use::initTags(Start, End);
137 if (DescBytes != 0) {
138 auto *DescInfo = reinterpret_cast<DescriptorInfo *>(Storage + DescBytes);
139 DescInfo->SizeInBytes = DescBytes;
145 void *User::operator new(size_t Size, unsigned Us) {
146 return allocateFixedOperandUser(Size, Us, 0);
149 void *User::operator new(size_t Size, unsigned Us, unsigned DescBytes) {
150 return allocateFixedOperandUser(Size, Us, DescBytes);
153 void *User::operator new(size_t Size) {
154 // Allocate space for a single Use*
155 void *Storage = ::operator new(Size + sizeof(Use *));
156 Use **HungOffOperandList = static_cast<Use **>(Storage);
157 User *Obj = reinterpret_cast<User *>(HungOffOperandList + 1);
158 Obj->NumUserOperands = 0;
159 Obj->HasHungOffUses = true;
160 Obj->HasDescriptor = false;
161 *HungOffOperandList = nullptr;
165 //===----------------------------------------------------------------------===//
166 // User operator delete Implementation
167 //===----------------------------------------------------------------------===//
169 void User::operator delete(void *Usr) {
170 // Hung off uses use a single Use* before the User, while other subclasses
171 // use a Use[] allocated prior to the user.
172 User *Obj = static_cast<User *>(Usr);
173 if (Obj->HasHungOffUses) {
174 assert(!Obj->HasDescriptor && "not supported!");
176 Use **HungOffOperandList = static_cast<Use **>(Usr) - 1;
177 // drop the hung off uses.
178 Use::zap(*HungOffOperandList, *HungOffOperandList + Obj->NumUserOperands,
180 ::operator delete(HungOffOperandList);
181 } else if (Obj->HasDescriptor) {
182 Use *UseBegin = static_cast<Use *>(Usr) - Obj->NumUserOperands;
183 Use::zap(UseBegin, UseBegin + Obj->NumUserOperands, /* Delete */ false);
185 auto *DI = reinterpret_cast<DescriptorInfo *>(UseBegin) - 1;
186 uint8_t *Storage = reinterpret_cast<uint8_t *>(DI) - DI->SizeInBytes;
187 ::operator delete(Storage);
189 Use *Storage = static_cast<Use *>(Usr) - Obj->NumUserOperands;
190 Use::zap(Storage, Storage + Obj->NumUserOperands,
192 ::operator delete(Storage);
196 //===----------------------------------------------------------------------===//
198 //===----------------------------------------------------------------------===//
200 Operator::~Operator() {
201 llvm_unreachable("should never destroy an Operator");
204 } // End llvm namespace