LLVM  6.0.0svn
SlotIndexes.cpp
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1 //===-- SlotIndexes.cpp - Slot Indexes Pass ------------------------------===//
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 
11 #include "llvm/ADT/Statistic.h"
14 #include "llvm/Support/Debug.h"
16 
17 using namespace llvm;
18 
19 #define DEBUG_TYPE "slotindexes"
20 
21 char SlotIndexes::ID = 0;
23  "Slot index numbering", false, false)
24 
25 STATISTIC(NumLocalRenum, "Number of local renumberings");
26 STATISTIC(NumGlobalRenum, "Number of global renumberings");
27 
28 void SlotIndexes::getAnalysisUsage(AnalysisUsage &au) const {
29  au.setPreservesAll();
31 }
32 
34  mi2iMap.clear();
35  MBBRanges.clear();
36  idx2MBBMap.clear();
37  indexList.clear();
38  ileAllocator.Reset();
39 }
40 
42 
43  // Compute numbering as follows:
44  // Grab an iterator to the start of the index list.
45  // Iterate over all MBBs, and within each MBB all MIs, keeping the MI
46  // iterator in lock-step (though skipping it over indexes which have
47  // null pointers in the instruction field).
48  // At each iteration assert that the instruction pointed to in the index
49  // is the same one pointed to by the MI iterator. This
50 
51  // FIXME: This can be simplified. The mi2iMap_, Idx2MBBMap, etc. should
52  // only need to be set up once after the first numbering is computed.
53 
54  mf = &fn;
55 
56  // Check that the list contains only the sentinal.
57  assert(indexList.empty() && "Index list non-empty at initial numbering?");
58  assert(idx2MBBMap.empty() &&
59  "Index -> MBB mapping non-empty at initial numbering?");
60  assert(MBBRanges.empty() &&
61  "MBB -> Index mapping non-empty at initial numbering?");
62  assert(mi2iMap.empty() &&
63  "MachineInstr -> Index mapping non-empty at initial numbering?");
64 
65  unsigned index = 0;
66  MBBRanges.resize(mf->getNumBlockIDs());
67  idx2MBBMap.reserve(mf->size());
68 
69  indexList.push_back(createEntry(nullptr, index));
70 
71  // Iterate over the function.
72  for (MachineBasicBlock &MBB : *mf) {
73  // Insert an index for the MBB start.
74  SlotIndex blockStartIndex(&indexList.back(), SlotIndex::Slot_Block);
75 
76  for (MachineInstr &MI : MBB) {
77  if (MI.isDebugValue())
78  continue;
79 
80  // Insert a store index for the instr.
81  indexList.push_back(createEntry(&MI, index += SlotIndex::InstrDist));
82 
83  // Save this base index in the maps.
84  mi2iMap.insert(std::make_pair(
85  &MI, SlotIndex(&indexList.back(), SlotIndex::Slot_Block)));
86  }
87 
88  // We insert one blank instructions between basic blocks.
89  indexList.push_back(createEntry(nullptr, index += SlotIndex::InstrDist));
90 
91  MBBRanges[MBB.getNumber()].first = blockStartIndex;
92  MBBRanges[MBB.getNumber()].second = SlotIndex(&indexList.back(),
93  SlotIndex::Slot_Block);
94  idx2MBBMap.push_back(IdxMBBPair(blockStartIndex, &MBB));
95  }
96 
97  // Sort the Idx2MBBMap
98  std::sort(idx2MBBMap.begin(), idx2MBBMap.end(), Idx2MBBCompare());
99 
100  DEBUG(mf->print(dbgs(), this));
101 
102  // And we're done!
103  return false;
104 }
105 
107  assert(!MI.isBundledWithPred() &&
108  "Use removeSingleMachineInstrFromMaps() instread");
109  Mi2IndexMap::iterator mi2iItr = mi2iMap.find(&MI);
110  if (mi2iItr == mi2iMap.end())
111  return;
112 
113  SlotIndex MIIndex = mi2iItr->second;
114  IndexListEntry &MIEntry = *MIIndex.listEntry();
115  assert(MIEntry.getInstr() == &MI && "Instruction indexes broken.");
116  mi2iMap.erase(mi2iItr);
117  // FIXME: Eventually we want to actually delete these indexes.
118  MIEntry.setInstr(nullptr);
119 }
120 
122  Mi2IndexMap::iterator mi2iItr = mi2iMap.find(&MI);
123  if (mi2iItr == mi2iMap.end())
124  return;
125 
126  SlotIndex MIIndex = mi2iItr->second;
127  IndexListEntry &MIEntry = *MIIndex.listEntry();
128  assert(MIEntry.getInstr() == &MI && "Instruction indexes broken.");
129  mi2iMap.erase(mi2iItr);
130 
131  // When removing the first instruction of a bundle update mapping to next
132  // instruction.
133  if (MI.isBundledWithSucc()) {
134  // Only the first instruction of a bundle should have an index assigned.
135  assert(!MI.isBundledWithPred() && "Should have first bundle isntruction");
136 
137  MachineBasicBlock::instr_iterator Next = std::next(MI.getIterator());
138  MachineInstr &NextMI = *Next;
139  MIEntry.setInstr(&NextMI);
140  mi2iMap.insert(std::make_pair(&NextMI, MIIndex));
141  return;
142  } else {
143  // FIXME: Eventually we want to actually delete these indexes.
144  MIEntry.setInstr(nullptr);
145  }
146 }
147 
149  // Renumber updates the index of every element of the index list.
150  DEBUG(dbgs() << "\n*** Renumbering SlotIndexes ***\n");
151  ++NumGlobalRenum;
152 
153  unsigned index = 0;
154 
155  for (IndexList::iterator I = indexList.begin(), E = indexList.end();
156  I != E; ++I) {
157  I->setIndex(index);
158  index += SlotIndex::InstrDist;
159  }
160 }
161 
162 // Renumber indexes locally after curItr was inserted, but failed to get a new
163 // index.
165  // Number indexes with half the default spacing so we can catch up quickly.
166  const unsigned Space = SlotIndex::InstrDist/2;
167  static_assert((Space & 3) == 0, "InstrDist must be a multiple of 2*NUM");
168 
169  IndexList::iterator startItr = std::prev(curItr);
170  unsigned index = startItr->getIndex();
171  do {
172  curItr->setIndex(index += Space);
173  ++curItr;
174  // If the next index is bigger, we have caught up.
175  } while (curItr != indexList.end() && curItr->getIndex() <= index);
176 
177  DEBUG(dbgs() << "\n*** Renumbered SlotIndexes " << startItr->getIndex() << '-'
178  << index << " ***\n");
179  ++NumLocalRenum;
180 }
181 
182 // Repair indexes after adding and removing instructions.
186  // FIXME: Is this really necessary? The only caller repairIntervalsForRange()
187  // does the same thing.
188  // Find anchor points, which are at the beginning/end of blocks or at
189  // instructions that already have indexes.
190  while (Begin != MBB->begin() && !hasIndex(*Begin))
191  --Begin;
192  while (End != MBB->end() && !hasIndex(*End))
193  ++End;
194 
195  bool includeStart = (Begin == MBB->begin());
196  SlotIndex startIdx;
197  if (includeStart)
198  startIdx = getMBBStartIdx(MBB);
199  else
200  startIdx = getInstructionIndex(*Begin);
201 
202  SlotIndex endIdx;
203  if (End == MBB->end())
204  endIdx = getMBBEndIdx(MBB);
205  else
206  endIdx = getInstructionIndex(*End);
207 
208  // FIXME: Conceptually, this code is implementing an iterator on MBB that
209  // optionally includes an additional position prior to MBB->begin(), indicated
210  // by the includeStart flag. This is done so that we can iterate MIs in a MBB
211  // in parallel with SlotIndexes, but there should be a better way to do this.
212  IndexList::iterator ListB = startIdx.listEntry()->getIterator();
213  IndexList::iterator ListI = endIdx.listEntry()->getIterator();
215  bool pastStart = false;
216  while (ListI != ListB || MBBI != Begin || (includeStart && !pastStart)) {
217  assert(ListI->getIndex() >= startIdx.getIndex() &&
218  (includeStart || !pastStart) &&
219  "Decremented past the beginning of region to repair.");
220 
221  MachineInstr *SlotMI = ListI->getInstr();
222  MachineInstr *MI = (MBBI != MBB->end() && !pastStart) ? &*MBBI : nullptr;
223  bool MBBIAtBegin = MBBI == Begin && (!includeStart || pastStart);
224 
225  if (SlotMI == MI && !MBBIAtBegin) {
226  --ListI;
227  if (MBBI != Begin)
228  --MBBI;
229  else
230  pastStart = true;
231  } else if (MI && mi2iMap.find(MI) == mi2iMap.end()) {
232  if (MBBI != Begin)
233  --MBBI;
234  else
235  pastStart = true;
236  } else {
237  --ListI;
238  if (SlotMI)
240  }
241  }
242 
243  // In theory this could be combined with the previous loop, but it is tricky
244  // to update the IndexList while we are iterating it.
245  for (MachineBasicBlock::iterator I = End; I != Begin;) {
246  --I;
247  MachineInstr &MI = *I;
248  if (!MI.isDebugValue() && mi2iMap.find(&MI) == mi2iMap.end())
250  }
251 }
252 
253 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
255  for (IndexList::const_iterator itr = indexList.begin();
256  itr != indexList.end(); ++itr) {
257  dbgs() << itr->getIndex() << " ";
258 
259  if (itr->getInstr()) {
260  dbgs() << *itr->getInstr();
261  } else {
262  dbgs() << "\n";
263  }
264  }
265 
266  for (unsigned i = 0, e = MBBRanges.size(); i != e; ++i)
267  dbgs() << "BB#" << i << "\t[" << MBBRanges[i].first << ';'
268  << MBBRanges[i].second << ")\n";
269 }
270 #endif
271 
272 // Print a SlotIndex to a raw_ostream.
273 void SlotIndex::print(raw_ostream &os) const {
274  if (isValid())
275  os << listEntry()->getIndex() << "Berd"[getSlot()];
276  else
277  os << "invalid";
278 }
279 
280 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
281 // Dump a SlotIndex to stderr.
283  print(dbgs());
284  dbgs() << "\n";
285 }
286 #endif
287 
void push_back(const T &Elt)
Definition: SmallVector.h:212
void renumberIndexes()
Renumber the index list, providing space for new instructions.
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
#define LLVM_DUMP_METHOD
Mark debug helper function definitions like dump() that should not be stripped from debug builds...
Definition: Compiler.h:449
void removeSingleMachineInstrFromMaps(MachineInstr &MI)
Removes a single machine instruction MI from the mapping.
unsigned getNumBlockIDs() const
getNumBlockIDs - Return the number of MBB ID&#39;s allocated.
bool isBundledWithPred() const
Return true if this instruction is part of a bundle, and it is not the first instruction in the bundl...
Definition: MachineInstr.h:247
unsigned size() const
void removeMachineInstrFromMaps(MachineInstr &MI)
Removes machine instruction (bundle) MI from the mapping.
STATISTIC(NumFunctions, "Total number of functions")
void reserve(size_type N)
Definition: SmallVector.h:380
The default distance between instructions as returned by distance().
Definition: SlotIndexes.h:138
std::pair< iterator, bool > insert(const std::pair< KeyT, ValueT > &KV)
Definition: DenseMap.h:191
#define DEBUG_TYPE
Definition: SlotIndexes.cpp:19
void Reset()
Deallocate all but the current slab and reset the current pointer to the beginning of it...
Definition: Allocator.h:192
bool isBundledWithSucc() const
Return true if this instruction is part of a bundle, and it is not the last instruction in the bundle...
Definition: MachineInstr.h:251
SlotIndex getInstructionIndex(const MachineInstr &MI) const
Returns the base index for the given instruction.
Definition: SlotIndexes.h:414
SlotIndexes pass.
Definition: SlotIndexes.h:331
iterator find(const_arg_type_t< KeyT > Val)
Definition: DenseMap.h:146
void dump() const
Dump this index to stderr.
SlotIndex insertMachineInstrInMaps(MachineInstr &MI, bool Late=false)
Insert the given machine instruction into the mapping.
Definition: SlotIndexes.h:577
MachineInstr * getInstr() const
Definition: SlotIndexes.h:54
bool erase(const KeyT &Val)
Definition: DenseMap.h:268
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - Subclasses that override getAnalysisUsage must call this.
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator begin()
Definition: SmallVector.h:116
bool hasIndex(const MachineInstr &instr) const
Returns true if the given machine instr is mapped to an index, otherwise returns false.
Definition: SlotIndexes.h:409
SlotIndex getMBBStartIdx(unsigned Num) const
Returns the first index in the given basic block number.
Definition: SlotIndexes.h:487
Represent the analysis usage information of a pass.
std::pair< SlotIndex, MachineBasicBlock * > IdxMBBPair
Definition: SlotIndexes.h:312
static const unsigned End
self_iterator getIterator()
Definition: ilist_node.h:82
void setInstr(MachineInstr *mi)
Definition: SlotIndexes.h:55
void dump() const
Dump the indexes.
SlotIndex getMBBEndIdx(unsigned Num) const
Returns the last index in the given basic block number.
Definition: SlotIndexes.h:497
Iterator for intrusive lists based on ilist_node.
bool isDebugValue() const
Definition: MachineInstr.h:816
raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
Definition: Debug.cpp:132
void push_back(pointer val)
Definition: ilist.h:326
void repairIndexesInRange(MachineBasicBlock *MBB, MachineBasicBlock::iterator Begin, MachineBasicBlock::iterator End)
Repair indexes after adding and removing instructions.
Representation of each machine instruction.
Definition: MachineInstr.h:59
static char ID
Definition: SlotIndexes.h:369
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator end()
Definition: SmallVector.h:120
This class represents an entry in the slot index list held in the SlotIndexes pass.
Definition: SlotIndexes.h:47
bool runOnMachineFunction(MachineFunction &fn) override
runOnMachineFunction - This method must be overloaded to perform the desired machine code transformat...
Definition: SlotIndexes.cpp:41
void clear()
Definition: ilist.h:322
void releaseMemory() override
releaseMemory() - This member can be implemented by a pass if it wants to be able to release its memo...
Definition: SlotIndexes.cpp:33
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:61
#define I(x, y, z)
Definition: MD5.cpp:58
iterator end()
Definition: DenseMap.h:79
virtual void print(raw_ostream &OS, const Module *M) const
print - Print out the internal state of the pass.
Definition: Pass.cpp:123
INITIALIZE_PASS(SlotIndexes, DEBUG_TYPE, "Slot index numbering", false, false) STATISTIC(NumLocalRenum
LLVM_NODISCARD bool empty() const
Definition: DenseMap.h:93
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:44
#define DEBUG(X)
Definition: Debug.h:118
IRTranslator LLVM IR MI
void print(raw_ostream &os) const
Print this index to the given raw_ostream.
void sort(Policy policy, RandomAccessIterator Start, RandomAccessIterator End, const Comparator &Comp=Comparator())
Definition: Parallel.h:199
SlotIndex - An opaque wrapper around machine indexes.
Definition: SlotIndexes.h:84
Number of local renumberings
Definition: SlotIndexes.cpp:25