LLVM  4.0.0
User.cpp
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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 
15 namespace llvm {
16 class BasicBlock;
17 
18 //===----------------------------------------------------------------------===//
19 // User Class
20 //===----------------------------------------------------------------------===//
21 
22 void User::anchor() {}
23 
25  if (From == To) return; // Duh what?
26 
27  assert((!isa<Constant>(this) || isa<GlobalValue>(this)) &&
28  "Cannot call User::replaceUsesOfWith on a constant!");
29 
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...
36  }
37 }
38 
39 //===----------------------------------------------------------------------===//
40 // User allocHungoffUses Implementation
41 //===----------------------------------------------------------------------===//
42 
43 void User::allocHungoffUses(unsigned N, bool IsPhi) {
44  assert(HasHungOffUses && "alloc must have hung off uses");
45 
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");
50 
51  // Allocate the array of Uses, followed by a pointer (with bottom bit set) to
52  // the User.
53  size_t size = N * sizeof(Use) + sizeof(Use::UserRef);
54  if (IsPhi)
55  size += N * sizeof(BasicBlock *);
56  Use *Begin = static_cast<Use*>(::operator new(size));
57  Use *End = Begin + N;
58  (void) new(End) Use::UserRef(const_cast<User*>(this), 1);
59  setOperandList(Use::initTags(Begin, End));
60 }
61 
62 void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) {
63  assert(HasHungOffUses && "realloc must have hung off uses");
64 
65  unsigned OldNumUses = getNumOperands();
66 
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");
70 
71  Use *OldOps = getOperandList();
72  allocHungoffUses(NewNumUses, IsPhi);
73  Use *NewOps = getOperandList();
74 
75  // Now copy from the old operands list to the new one.
76  std::copy(OldOps, OldOps + OldNumUses, NewOps);
77 
78  // If this is a Phi, then we need to copy the BB pointers too.
79  if (IsPhi) {
80  auto *OldPtr =
81  reinterpret_cast<char *>(OldOps + OldNumUses) + sizeof(Use::UserRef);
82  auto *NewPtr =
83  reinterpret_cast<char *>(NewOps + NewNumUses) + sizeof(Use::UserRef);
84  std::copy(OldPtr, OldPtr + (OldNumUses * sizeof(BasicBlock *)), NewPtr);
85  }
86  Use::zap(OldOps, OldOps + OldNumUses, true);
87 }
88 
89 
90 // This is a private struct used by `User` to track the co-allocated descriptor
91 // section.
94 };
95 
97  auto MutableARef = const_cast<User *>(this)->getDescriptor();
98  return {MutableARef.begin(), MutableARef.end()};
99 }
100 
102  assert(HasDescriptor && "Don't call otherwise!");
103  assert(!HasHungOffUses && "Invariant!");
104 
105  auto *DI = reinterpret_cast<DescriptorInfo *>(getIntrusiveOperands()) - 1;
106  assert(DI->SizeInBytes != 0 && "Should not have had a descriptor otherwise!");
107 
109  reinterpret_cast<uint8_t *>(DI) - DI->SizeInBytes, DI->SizeInBytes);
110 }
111 
112 //===----------------------------------------------------------------------===//
113 // User operator new Implementations
114 //===----------------------------------------------------------------------===//
115 
116 void *User::allocateFixedOperandUser(size_t Size, unsigned Us,
117  unsigned DescBytes) {
118  assert(Us < (1u << NumUserOperandsBits) && "Too many operands");
119 
120  static_assert(sizeof(DescriptorInfo) % sizeof(void *) == 0, "Required below");
121 
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");
126 
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);
136 
137  if (DescBytes != 0) {
138  auto *DescInfo = reinterpret_cast<DescriptorInfo *>(Storage + DescBytes);
139  DescInfo->SizeInBytes = DescBytes;
140  }
141 
142  return Obj;
143 }
144 
145 void *User::operator new(size_t Size, unsigned Us) {
146  return allocateFixedOperandUser(Size, Us, 0);
147 }
148 
149 void *User::operator new(size_t Size, unsigned Us, unsigned DescBytes) {
150  return allocateFixedOperandUser(Size, Us, DescBytes);
151 }
152 
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;
162  return Obj;
163 }
164 
165 //===----------------------------------------------------------------------===//
166 // User operator delete Implementation
167 //===----------------------------------------------------------------------===//
168 
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!");
175 
176  Use **HungOffOperandList = static_cast<Use **>(Usr) - 1;
177  // drop the hung off uses.
178  Use::zap(*HungOffOperandList, *HungOffOperandList + Obj->NumUserOperands,
179  /* Delete */ true);
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);
184 
185  auto *DI = reinterpret_cast<DescriptorInfo *>(UseBegin) - 1;
186  uint8_t *Storage = reinterpret_cast<uint8_t *>(DI) - DI->SizeInBytes;
187  ::operator delete(Storage);
188  } else {
189  Use *Storage = static_cast<Use *>(Usr) - Obj->NumUserOperands;
190  Use::zap(Storage, Storage + Obj->NumUserOperands,
191  /* Delete */ false);
192  ::operator delete(Storage);
193  }
194 }
195 
196 //===----------------------------------------------------------------------===//
197 // Operator Class
198 //===----------------------------------------------------------------------===//
199 
201  llvm_unreachable("should never destroy an Operator");
202 }
203 
204 } // End llvm namespace
unsigned HasDescriptor
Definition: Value.h:117
size_t i
Various leaf nodes.
Definition: ISDOpcodes.h:60
unsigned getNumOperands() const
Definition: User.h:167
A Use represents the edge between a Value definition and its users.
Definition: Use.h:56
void growHungoffUses(unsigned N, bool IsPhi=false)
Grow the number of hung off uses.
Definition: User.cpp:62
Use * getOperandList()
Definition: User.h:138
intptr_t SizeInBytes
Definition: User.cpp:93
unsigned HasHungOffUses
Definition: Value.h:116
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: APInt.h:33
~Operator() override
Definition: User.cpp:200
static GCRegistry::Add< CoreCLRGC > E("coreclr","CoreCLR-compatible GC")
void replaceUsesOfWith(Value *From, Value *To)
Replace uses of one Value with another.
Definition: User.cpp:24
LLVM Basic Block Representation.
Definition: BasicBlock.h:51
PointerIntPair - This class implements a pair of a pointer and small integer.
static Use * initTags(Use *Start, Use *Stop)
Initializes the waymarking tags on an array of Uses.
Definition: Use.cpp:57
static const unsigned End
Value * getOperand(unsigned i) const
Definition: User.h:145
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
PointerIntPair< User *, 1, unsigned > UserRef
Definition: Use.h:66
unsigned NumUserOperands
Definition: Value.h:111
void setOperand(unsigned i, Value *Val)
Definition: User.h:150
ArrayRef< const uint8_t > getDescriptor() const
Returns the descriptor co-allocated with this User instance.
Definition: User.cpp:96
#define N
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
LLVM Value Representation.
Definition: Value.h:71
void allocHungoffUses(unsigned N, bool IsPhi=false)
Allocate the array of Uses, followed by a pointer (with bottom bit set) to the User.
Definition: User.cpp:43
static void zap(Use *Start, const Use *Stop, bool del=false)
Destroys Use operands when the number of operands of a User changes.
Definition: Use.cpp:87