LLVM  6.0.0svn
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 #include "llvm/IR/Operator.h"
14 
15 namespace llvm {
16 class BasicBlock;
17 
18 //===----------------------------------------------------------------------===//
19 // User Class
20 //===----------------------------------------------------------------------===//
21 
23  if (From == To) return; // Duh what?
24 
25  assert((!isa<Constant>(this) || isa<GlobalValue>(this)) &&
26  "Cannot call User::replaceUsesOfWith on a constant!");
27 
28  for (unsigned i = 0, E = getNumOperands(); i != E; ++i)
29  if (getOperand(i) == From) { // Is This operand is pointing to oldval?
30  // The side effects of this setOperand call include linking to
31  // "To", adding "this" to the uses list of To, and
32  // most importantly, removing "this" from the use list of "From".
33  setOperand(i, To); // Fix it now...
34  }
35 }
36 
37 //===----------------------------------------------------------------------===//
38 // User allocHungoffUses Implementation
39 //===----------------------------------------------------------------------===//
40 
41 void User::allocHungoffUses(unsigned N, bool IsPhi) {
42  assert(HasHungOffUses && "alloc must have hung off uses");
43 
44  static_assert(alignof(Use) >= alignof(Use::UserRef),
45  "Alignment is insufficient for 'hung-off-uses' pieces");
46  static_assert(alignof(Use::UserRef) >= alignof(BasicBlock *),
47  "Alignment is insufficient for 'hung-off-uses' pieces");
48 
49  // Allocate the array of Uses, followed by a pointer (with bottom bit set) to
50  // the User.
51  size_t size = N * sizeof(Use) + sizeof(Use::UserRef);
52  if (IsPhi)
53  size += N * sizeof(BasicBlock *);
54  Use *Begin = static_cast<Use*>(::operator new(size));
55  Use *End = Begin + N;
56  (void) new(End) Use::UserRef(const_cast<User*>(this), 1);
57  setOperandList(Use::initTags(Begin, End));
58 }
59 
60 void User::growHungoffUses(unsigned NewNumUses, bool IsPhi) {
61  assert(HasHungOffUses && "realloc must have hung off uses");
62 
63  unsigned OldNumUses = getNumOperands();
64 
65  // We don't support shrinking the number of uses. We wouldn't have enough
66  // space to copy the old uses in to the new space.
67  assert(NewNumUses > OldNumUses && "realloc must grow num uses");
68 
69  Use *OldOps = getOperandList();
70  allocHungoffUses(NewNumUses, IsPhi);
71  Use *NewOps = getOperandList();
72 
73  // Now copy from the old operands list to the new one.
74  std::copy(OldOps, OldOps + OldNumUses, NewOps);
75 
76  // If this is a Phi, then we need to copy the BB pointers too.
77  if (IsPhi) {
78  auto *OldPtr =
79  reinterpret_cast<char *>(OldOps + OldNumUses) + sizeof(Use::UserRef);
80  auto *NewPtr =
81  reinterpret_cast<char *>(NewOps + NewNumUses) + sizeof(Use::UserRef);
82  std::copy(OldPtr, OldPtr + (OldNumUses * sizeof(BasicBlock *)), NewPtr);
83  }
84  Use::zap(OldOps, OldOps + OldNumUses, true);
85 }
86 
87 
88 // This is a private struct used by `User` to track the co-allocated descriptor
89 // section.
92 };
93 
95  auto MutableARef = const_cast<User *>(this)->getDescriptor();
96  return {MutableARef.begin(), MutableARef.end()};
97 }
98 
100  assert(HasDescriptor && "Don't call otherwise!");
101  assert(!HasHungOffUses && "Invariant!");
102 
103  auto *DI = reinterpret_cast<DescriptorInfo *>(getIntrusiveOperands()) - 1;
104  assert(DI->SizeInBytes != 0 && "Should not have had a descriptor otherwise!");
105 
107  reinterpret_cast<uint8_t *>(DI) - DI->SizeInBytes, DI->SizeInBytes);
108 }
109 
110 //===----------------------------------------------------------------------===//
111 // User operator new Implementations
112 //===----------------------------------------------------------------------===//
113 
114 void *User::allocateFixedOperandUser(size_t Size, unsigned Us,
115  unsigned DescBytes) {
116  assert(Us < (1u << NumUserOperandsBits) && "Too many operands");
117 
118  static_assert(sizeof(DescriptorInfo) % sizeof(void *) == 0, "Required below");
119 
120  unsigned DescBytesToAllocate =
121  DescBytes == 0 ? 0 : (DescBytes + sizeof(DescriptorInfo));
122  assert(DescBytesToAllocate % sizeof(void *) == 0 &&
123  "We need this to satisfy alignment constraints for Uses");
124 
125  uint8_t *Storage = static_cast<uint8_t *>(
126  ::operator new(Size + sizeof(Use) * Us + DescBytesToAllocate));
127  Use *Start = reinterpret_cast<Use *>(Storage + DescBytesToAllocate);
128  Use *End = Start + Us;
129  User *Obj = reinterpret_cast<User*>(End);
130  Obj->NumUserOperands = Us;
131  Obj->HasHungOffUses = false;
132  Obj->HasDescriptor = DescBytes != 0;
133  Use::initTags(Start, End);
134 
135  if (DescBytes != 0) {
136  auto *DescInfo = reinterpret_cast<DescriptorInfo *>(Storage + DescBytes);
137  DescInfo->SizeInBytes = DescBytes;
138  }
139 
140  return Obj;
141 }
142 
143 void *User::operator new(size_t Size, unsigned Us) {
144  return allocateFixedOperandUser(Size, Us, 0);
145 }
146 
147 void *User::operator new(size_t Size, unsigned Us, unsigned DescBytes) {
148  return allocateFixedOperandUser(Size, Us, DescBytes);
149 }
150 
151 void *User::operator new(size_t Size) {
152  // Allocate space for a single Use*
153  void *Storage = ::operator new(Size + sizeof(Use *));
154  Use **HungOffOperandList = static_cast<Use **>(Storage);
155  User *Obj = reinterpret_cast<User *>(HungOffOperandList + 1);
156  Obj->NumUserOperands = 0;
157  Obj->HasHungOffUses = true;
158  Obj->HasDescriptor = false;
159  *HungOffOperandList = nullptr;
160  return Obj;
161 }
162 
163 //===----------------------------------------------------------------------===//
164 // User operator delete Implementation
165 //===----------------------------------------------------------------------===//
166 
167 void User::operator delete(void *Usr) {
168  // Hung off uses use a single Use* before the User, while other subclasses
169  // use a Use[] allocated prior to the user.
170  User *Obj = static_cast<User *>(Usr);
171  if (Obj->HasHungOffUses) {
172  assert(!Obj->HasDescriptor && "not supported!");
173 
174  Use **HungOffOperandList = static_cast<Use **>(Usr) - 1;
175  // drop the hung off uses.
176  Use::zap(*HungOffOperandList, *HungOffOperandList + Obj->NumUserOperands,
177  /* Delete */ true);
178  ::operator delete(HungOffOperandList);
179  } else if (Obj->HasDescriptor) {
180  Use *UseBegin = static_cast<Use *>(Usr) - Obj->NumUserOperands;
181  Use::zap(UseBegin, UseBegin + Obj->NumUserOperands, /* Delete */ false);
182 
183  auto *DI = reinterpret_cast<DescriptorInfo *>(UseBegin) - 1;
184  uint8_t *Storage = reinterpret_cast<uint8_t *>(DI) - DI->SizeInBytes;
185  ::operator delete(Storage);
186  } else {
187  Use *Storage = static_cast<Use *>(Usr) - Obj->NumUserOperands;
188  Use::zap(Storage, Storage + Obj->NumUserOperands,
189  /* Delete */ false);
190  ::operator delete(Storage);
191  }
192 }
193 
194 } // 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:60
intptr_t SizeInBytes
Definition: User.cpp:91
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:154
void replaceUsesOfWith(Value *From, Value *To)
Replace uses of one Value with another.
Definition: User.cpp:22
const Use * getOperandList() const
Definition: User.h:147
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:94
static const unsigned End
unsigned getNumOperands() const
Definition: User.h:176
unsigned NumUserOperands
Definition: Value.h:115
void setOperand(unsigned i, Value *Val)
Definition: User.h:159
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:41
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