#ifndef LLVM_CODEGEN_SLOTINDEXES_H
#define LLVM_CODEGEN_SLOTINDEXES_H
-#include "llvm/CodeGen/MachineInstrBundle.h"
-#include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/IntervalMap.h"
#include "llvm/ADT/PointerIntPair.h"
-#include "llvm/ADT/ilist.h"
#include "llvm/ADT/SmallVector.h"
-#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/ilist.h"
+#include "llvm/CodeGen/MachineFunction.h"
+#include "llvm/CodeGen/MachineFunctionPass.h"
+#include "llvm/CodeGen/MachineInstrBundle.h"
#include "llvm/Support/Allocator.h"
namespace llvm {
this->index = index;
}
+#ifdef EXPENSIVE_CHECKS
+ // When EXPENSIVE_CHECKS is defined, "erased" index list entries will
+ // actually be moved to a "graveyard" list, and have their pointers
+ // poisoned, so that dangling SlotIndex access can be reliably detected.
+ void setPoison() {
+ intptr_t tmp = reinterpret_cast<intptr_t>(mi);
+ assert(((tmp & 0x1) == 0x0) && "Pointer already poisoned?");
+ tmp |= 0x1;
+ mi = reinterpret_cast<MachineInstr*>(tmp);
+ }
+
+ bool isPoisoned() const { return (reinterpret_cast<intptr_t>(mi) & 0x1) == 0x1; }
+#endif // EXPENSIVE_CHECKS
+
};
template <>
/// SlotIndex - An opaque wrapper around machine indexes.
class SlotIndex {
friend class SlotIndexes;
- friend struct DenseMapInfo<SlotIndex>;
enum Slot {
/// Basic block boundary. Used for live ranges entering and leaving a
IndexListEntry* listEntry() const {
assert(isValid() && "Attempt to compare reserved index.");
+#ifdef EXPENSIVE_CHECKS
+ assert(!lie.getPointer()->isPoisoned() &&
+ "Attempt to access deleted list-entry.");
+#endif // EXPENSIVE_CHECKS
return lie.getPointer();
}
- int getIndex() const {
+ unsigned getIndex() const {
return listEntry()->getIndex() | getSlot();
}
return static_cast<Slot>(lie.getInt());
}
- static inline unsigned getHashValue(const SlotIndex &v) {
- void *ptrVal = v.lie.getOpaqueValue();
- return (unsigned((intptr_t)ptrVal)) ^ (unsigned((intptr_t)ptrVal) >> 9);
- }
-
public:
enum {
/// The default distance between instructions as returned by distance().
InstrDist = 4 * Slot_Count
};
- static inline SlotIndex getEmptyKey() {
- return SlotIndex(0, 1);
- }
-
- static inline SlotIndex getTombstoneKey() {
- return SlotIndex(0, 2);
- }
-
/// Construct an invalid index.
SlotIndex() : lie(0, 0) {}
};
- /// DenseMapInfo specialization for SlotIndex.
- template <>
- struct DenseMapInfo<SlotIndex> {
- static inline SlotIndex getEmptyKey() {
- return SlotIndex::getEmptyKey();
- }
- static inline SlotIndex getTombstoneKey() {
- return SlotIndex::getTombstoneKey();
- }
- static inline unsigned getHashValue(const SlotIndex &v) {
- return SlotIndex::getHashValue(v);
- }
- static inline bool isEqual(const SlotIndex &LHS, const SlotIndex &RHS) {
- return (LHS == RHS);
- }
- };
-
template <> struct isPodLike<SlotIndex> { static const bool value = true; };
-
inline raw_ostream& operator<<(raw_ostream &os, SlotIndex li) {
li.print(os);
return os;
typedef ilist<IndexListEntry> IndexList;
IndexList indexList;
+#ifdef EXPENSIVE_CHECKS
+ IndexList graveyardList;
+#endif // EXPENSIVE_CHECKS
+
MachineFunction *mf;
typedef DenseMap<const MachineInstr*, SlotIndex> Mi2IndexMap;
/// Renumber the index list, providing space for new instructions.
void renumberIndexes();
+ /// Repair indexes after adding and removing instructions.
+ void repairIndexesInRange(MachineBasicBlock *MBB,
+ MachineBasicBlock::iterator Begin,
+ MachineBasicBlock::iterator End);
+
/// Returns the zero index for this analysis.
SlotIndex getZeroIndex() {
assert(indexList.front().getIndex() == 0 && "First index is not 0?");
return index.isValid() ? index.listEntry()->getInstr() : 0;
}
- /// Returns the next non-null index.
- SlotIndex getNextNonNullIndex(SlotIndex index) {
- IndexList::iterator itr(index.listEntry());
- ++itr;
- while (itr != indexList.end() && itr->getInstr() == 0) { ++itr; }
- return SlotIndex(itr, index.getSlot());
+ /// Returns the next non-null index, if one exists.
+ /// Otherwise returns getLastIndex().
+ SlotIndex getNextNonNullIndex(SlotIndex Index) {
+ IndexList::iterator I = Index.listEntry();
+ IndexList::iterator E = indexList.end();
+ while (++I != E)
+ if (I->getInstr())
+ return SlotIndex(I, Index.getSlot());
+ // We reached the end of the function.
+ return getLastIndex();
}
/// getIndexBefore - Returns the index of the last indexed instruction
- /// before MI, or the the start index of its basic block.
+ /// before MI, or the start index of its basic block.
/// MI is not required to have an index.
SlotIndex getIndexBefore(const MachineInstr *MI) const {
const MachineBasicBlock *MBB = MI->getParent();
void insertMBBInMaps(MachineBasicBlock *mbb) {
MachineFunction::iterator nextMBB =
llvm::next(MachineFunction::iterator(mbb));
- IndexListEntry *startEntry = createEntry(0, 0);
- IndexListEntry *stopEntry = createEntry(0, 0);
- IndexListEntry *nextEntry = 0;
+ IndexListEntry *startEntry = 0;
+ IndexListEntry *endEntry = 0;
+ IndexList::iterator newItr;
if (nextMBB == mbb->getParent()->end()) {
- nextEntry = indexList.end();
+ startEntry = &indexList.back();
+ endEntry = createEntry(0, 0);
+ newItr = indexList.insertAfter(startEntry, endEntry);
} else {
- nextEntry = getMBBStartIdx(nextMBB).listEntry();
+ startEntry = createEntry(0, 0);
+ endEntry = getMBBStartIdx(nextMBB).listEntry();
+ newItr = indexList.insert(endEntry, startEntry);
}
- indexList.insert(nextEntry, startEntry);
- indexList.insert(nextEntry, stopEntry);
-
SlotIndex startIdx(startEntry, SlotIndex::Slot_Block);
- SlotIndex endIdx(nextEntry, SlotIndex::Slot_Block);
+ SlotIndex endIdx(endEntry, SlotIndex::Slot_Block);
+
+ MachineFunction::iterator prevMBB(mbb);
+ assert(prevMBB != mbb->getParent()->end() &&
+ "Can't insert a new block at the beginning of a function.");
+ --prevMBB;
+ MBBRanges[prevMBB->getNumber()].second = startIdx;
assert(unsigned(mbb->getNumber()) == MBBRanges.size() &&
"Blocks must be added in order");
MBBRanges.push_back(std::make_pair(startIdx, endIdx));
-
idx2MBBMap.push_back(IdxMBBPair(startIdx, mbb));
- renumberIndexes();
+ renumberIndexes(newItr);
std::sort(idx2MBBMap.begin(), idx2MBBMap.end(), Idx2MBBCompare());
}
+ /// \brief Free the resources that were required to maintain a SlotIndex.
+ ///
+ /// Once an index is no longer needed (for instance because the instruction
+ /// at that index has been moved), the resources required to maintain the
+ /// index can be relinquished to reduce memory use and improve renumbering
+ /// performance. Any remaining SlotIndex objects that point to the same
+ /// index are left 'dangling' (much the same as a dangling pointer to a
+ /// freed object) and should not be accessed, except to destruct them.
+ ///
+ /// Like dangling pointers, access to dangling SlotIndexes can cause
+ /// painful-to-track-down bugs, especially if the memory for the index
+ /// previously pointed to has been re-used. To detect dangling SlotIndex
+ /// bugs, build with EXPENSIVE_CHECKS=1. This will cause "erased" indexes to
+ /// be retained in a graveyard instead of being freed. Operations on indexes
+ /// in the graveyard will trigger an assertion.
+ void eraseIndex(SlotIndex index) {
+ IndexListEntry *entry = index.listEntry();
+#ifdef EXPENSIVE_CHECKS
+ indexList.remove(entry);
+ graveyardList.push_back(entry);
+ entry->setPoison();
+#else
+ indexList.erase(entry);
+#endif
+ }
+
};
// Specialize IntervalMapInfo for half-open slot index intervals.
- template <typename> struct IntervalMapInfo;
- template <> struct IntervalMapInfo<SlotIndex> {
- static inline bool startLess(const SlotIndex &x, const SlotIndex &a) {
- return x < a;
- }
- static inline bool stopLess(const SlotIndex &b, const SlotIndex &x) {
- return b <= x;
- }
- static inline bool adjacent(const SlotIndex &a, const SlotIndex &b) {
- return a == b;
- }
+ template <>
+ struct IntervalMapInfo<SlotIndex> : IntervalMapHalfOpenInfo<SlotIndex> {
};
}
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