LLVM  7.0.0svn
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 
14 namespace llvm {
15 class BasicBlock;
16 
17 //===----------------------------------------------------------------------===//
18 // User Class
19 //===----------------------------------------------------------------------===//
20 
22  if (From == To) return; // Duh what?
23 
24  assert((!isa<Constant>(this) || isa<GlobalValue>(this)) &&
25  "Cannot call User::replaceUsesOfWith on a constant!");
26 
27  for (unsigned i = 0, E = getNumOperands(); i != E; ++i)
28  if (getOperand(i) == From) { // Is This operand is pointing to oldval?
29  // The side effects of this setOperand call include linking to
30  // "To", adding "this" to the uses list of To, and
31  // most importantly, removing "this" from the use list of "From".
32  setOperand(i, To); // Fix it now...
33  }
34 }
35 
36 //===----------------------------------------------------------------------===//
37 // User allocHungoffUses Implementation
38 //===----------------------------------------------------------------------===//
39 
40 void User::allocHungoffUses(unsigned N, bool IsPhi) {
41  assert(HasHungOffUses && "alloc must have hung off uses");
42 
43  static_assert(alignof(Use) >= alignof(Use::UserRef),
44  "Alignment is insufficient for 'hung-off-uses' pieces");
45  static_assert(alignof(Use::UserRef) >= alignof(BasicBlock *),
46  "Alignment is insufficient for 'hung-off-uses' pieces");
47 
48  // Allocate the array of Uses, followed by a pointer (with bottom bit set) to
49  // the User.
50  size_t size = N * sizeof(Use) + sizeof(Use::UserRef);
51  if (IsPhi)
52  size += N * sizeof(BasicBlock *);
53  Use *Begin = static_cast<Use*>(::operator new(size));
54  Use *End = Begin + N;
55  (void) new(End) Use::UserRef(const_cast<User*>(this), 1);
56  setOperandList(Use::initTags(Begin, End));
57 }
58 
59 void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) {
60  assert(HasHungOffUses && "realloc must have hung off uses");
61 
62  unsigned OldNumUses = getNumOperands();
63 
64  // We don't support shrinking the number of uses. We wouldn't have enough
65  // space to copy the old uses in to the new space.
66  assert(NewNumUses > OldNumUses && "realloc must grow num uses");
67 
68  Use *OldOps = getOperandList();
69  allocHungoffUses(NewNumUses, IsPhi);
70  Use *NewOps = getOperandList();
71 
72  // Now copy from the old operands list to the new one.
73  std::copy(OldOps, OldOps + OldNumUses, NewOps);
74 
75  // If this is a Phi, then we need to copy the BB pointers too.
76  if (IsPhi) {
77  auto *OldPtr =
78  reinterpret_cast<char *>(OldOps + OldNumUses) + sizeof(Use::UserRef);
79  auto *NewPtr =
80  reinterpret_cast<char *>(NewOps + NewNumUses) + sizeof(Use::UserRef);
81  std::copy(OldPtr, OldPtr + (OldNumUses * sizeof(BasicBlock *)), NewPtr);
82  }
83  Use::zap(OldOps, OldOps + OldNumUses, true);
84 }
85 
86 
87 // This is a private struct used by `User` to track the co-allocated descriptor
88 // section.
91 };
92 
94  auto MutableARef = const_cast<User *>(this)->getDescriptor();
95  return {MutableARef.begin(), MutableARef.end()};
96 }
97 
99  assert(HasDescriptor && "Don't call otherwise!");
100  assert(!HasHungOffUses && "Invariant!");
101 
102  auto *DI = reinterpret_cast<DescriptorInfo *>(getIntrusiveOperands()) - 1;
103  assert(DI->SizeInBytes != 0 && "Should not have had a descriptor otherwise!");
104 
106  reinterpret_cast<uint8_t *>(DI) - DI->SizeInBytes, DI->SizeInBytes);
107 }
108 
109 //===----------------------------------------------------------------------===//
110 // User operator new Implementations
111 //===----------------------------------------------------------------------===//
112 
113 void *User::allocateFixedOperandUser(size_t Size, unsigned Us,
114  unsigned DescBytes) {
115  assert(Us < (1u << NumUserOperandsBits) && "Too many operands");
116 
117  static_assert(sizeof(DescriptorInfo) % sizeof(void *) == 0, "Required below");
118 
119  unsigned DescBytesToAllocate =
120  DescBytes == 0 ? 0 : (DescBytes + sizeof(DescriptorInfo));
121  assert(DescBytesToAllocate % sizeof(void *) == 0 &&
122  "We need this to satisfy alignment constraints for Uses");
123 
124  uint8_t *Storage = static_cast<uint8_t *>(
125  ::operator new(Size + sizeof(Use) * Us + DescBytesToAllocate));
126  Use *Start = reinterpret_cast<Use *>(Storage + DescBytesToAllocate);
127  Use *End = Start + Us;
128  User *Obj = reinterpret_cast<User*>(End);
129  Obj->NumUserOperands = Us;
130  Obj->HasHungOffUses = false;
131  Obj->HasDescriptor = DescBytes != 0;
132  Use::initTags(Start, End);
133 
134  if (DescBytes != 0) {
135  auto *DescInfo = reinterpret_cast<DescriptorInfo *>(Storage + DescBytes);
136  DescInfo->SizeInBytes = DescBytes;
137  }
138 
139  return Obj;
140 }
141 
142 void *User::operator new(size_t Size, unsigned Us) {
143  return allocateFixedOperandUser(Size, Us, 0);
144 }
145 
146 void *User::operator new(size_t Size, unsigned Us, unsigned DescBytes) {
147  return allocateFixedOperandUser(Size, Us, DescBytes);
148 }
149 
150 void *User::operator new(size_t Size) {
151  // Allocate space for a single Use*
152  void *Storage = ::operator new(Size + sizeof(Use *));
153  Use **HungOffOperandList = static_cast<Use **>(Storage);
154  User *Obj = reinterpret_cast<User *>(HungOffOperandList + 1);
155  Obj->NumUserOperands = 0;
156  Obj->HasHungOffUses = true;
157  Obj->HasDescriptor = false;
158  *HungOffOperandList = nullptr;
159  return Obj;
160 }
161 
162 //===----------------------------------------------------------------------===//
163 // User operator delete Implementation
164 //===----------------------------------------------------------------------===//
165 
166 void User::operator delete(void *Usr) {
167  // Hung off uses use a single Use* before the User, while other subclasses
168  // use a Use[] allocated prior to the user.
169  User *Obj = static_cast<User *>(Usr);
170  if (Obj->HasHungOffUses) {
171  assert(!Obj->HasDescriptor && "not supported!");
172 
173  Use **HungOffOperandList = static_cast<Use **>(Usr) - 1;
174  // drop the hung off uses.
175  Use::zap(*HungOffOperandList, *HungOffOperandList + Obj->NumUserOperands,
176  /* Delete */ true);
177  ::operator delete(HungOffOperandList);
178  } else if (Obj->HasDescriptor) {
179  Use *UseBegin = static_cast<Use *>(Usr) - Obj->NumUserOperands;
180  Use::zap(UseBegin, UseBegin + Obj->NumUserOperands, /* Delete */ false);
181 
182  auto *DI = reinterpret_cast<DescriptorInfo *>(UseBegin) - 1;
183  uint8_t *Storage = reinterpret_cast<uint8_t *>(DI) - DI->SizeInBytes;
184  ::operator delete(Storage);
185  } else {
186  Use *Storage = static_cast<Use *>(Usr) - Obj->NumUserOperands;
187  Use::zap(Storage, Storage + Obj->NumUserOperands,
188  /* Delete */ false);
189  ::operator delete(Storage);
190  }
191 }
192 
193 } // End llvm namespace
unsigned HasDescriptor
Definition: Value.h:121
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
Various leaf nodes.
Definition: ISDOpcodes.h:60
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:59
intptr_t SizeInBytes
Definition: User.cpp:90
unsigned HasHungOffUses
Definition: Value.h:120
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory)...
Definition: APInt.h:33
Value * getOperand(unsigned i) const
Definition: User.h:170
void replaceUsesOfWith(Value *From, Value *To)
Replace uses of one Value with another.
Definition: User.cpp:21
const Use * getOperandList() const
Definition: User.h:163
LLVM Basic Block Representation.
Definition: BasicBlock.h:59
PointerIntPair - This class implements a pair of a pointer and small integer.
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
static Use * initTags(Use *Start, Use *Stop)
Initializes the waymarking tags on an array of Uses.
Definition: Use.cpp:57
ArrayRef< const uint8_t > getDescriptor() const
Returns the descriptor co-allocated with this User instance.
Definition: User.cpp:93
static const unsigned End
unsigned getNumOperands() const
Definition: User.h:192
auto size(R &&Range, typename std::enable_if< std::is_same< typename std::iterator_traits< decltype(Range.begin())>::iterator_category, std::random_access_iterator_tag >::value, void >::type *=nullptr) -> decltype(std::distance(Range.begin(), Range.end()))
Get the size of a range.
Definition: STLExtras.h:1032
unsigned NumUserOperands
Definition: Value.h:115
void setOperand(unsigned i, Value *Val)
Definition: User.h:175
PointerIntPair< User *, 1, unsigned, UserRefPointerTraits > UserRef
Definition: Use.h:78
#define N
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
LLVM Value Representation.
Definition: Value.h:73
constexpr char Size[]
Key for Kernel::Arg::Metadata::mSize.
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:40
OutputIt copy(R &&Range, OutputIt Out)
Definition: STLExtras.h:960
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