llvm-6502/include/llvm/CodeGen/SlotIndexes.h

711 lines
25 KiB
C++

//===- llvm/CodeGen/SlotIndexes.h - Slot indexes representation -*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements SlotIndex and related classes. The purpose of SlotIndex
// is to describe a position at which a register can become live, or cease to
// be live.
//
// SlotIndex is mostly a proxy for entries of the SlotIndexList, a class which
// is held is LiveIntervals and provides the real numbering. This allows
// LiveIntervals to perform largely transparent renumbering.
//===----------------------------------------------------------------------===//
#ifndef LLVM_CODEGEN_SLOTINDEXES_H
#define LLVM_CODEGEN_SLOTINDEXES_H
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/IntervalMap.h"
#include "llvm/ADT/PointerIntPair.h"
#include "llvm/ADT/SmallVector.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 class represents an entry in the slot index list held in the
/// SlotIndexes pass. It should not be used directly. See the
/// SlotIndex & SlotIndexes classes for the public interface to this
/// information.
class IndexListEntry : public ilist_node<IndexListEntry> {
MachineInstr *mi;
unsigned index;
public:
IndexListEntry(MachineInstr *mi, unsigned index) : mi(mi), index(index) {}
MachineInstr* getInstr() const { return mi; }
void setInstr(MachineInstr *mi) {
this->mi = mi;
}
unsigned getIndex() const { return index; }
void setIndex(unsigned index) {
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 <>
struct ilist_traits<IndexListEntry> : public ilist_default_traits<IndexListEntry> {
private:
mutable ilist_half_node<IndexListEntry> Sentinel;
public:
IndexListEntry *createSentinel() const {
return static_cast<IndexListEntry*>(&Sentinel);
}
void destroySentinel(IndexListEntry *) const {}
IndexListEntry *provideInitialHead() const { return createSentinel(); }
IndexListEntry *ensureHead(IndexListEntry*) const { return createSentinel(); }
static void noteHead(IndexListEntry*, IndexListEntry*) {}
void deleteNode(IndexListEntry *N) {}
private:
void createNode(const IndexListEntry &);
};
/// SlotIndex - An opaque wrapper around machine indexes.
class SlotIndex {
friend class SlotIndexes;
enum Slot {
/// Basic block boundary. Used for live ranges entering and leaving a
/// block without being live in the layout neighbor. Also used as the
/// def slot of PHI-defs.
Slot_Block,
/// Early-clobber register use/def slot. A live range defined at
/// Slot_EarlyCLobber interferes with normal live ranges killed at
/// Slot_Register. Also used as the kill slot for live ranges tied to an
/// early-clobber def.
Slot_EarlyClobber,
/// Normal register use/def slot. Normal instructions kill and define
/// register live ranges at this slot.
Slot_Register,
/// Dead def kill point. Kill slot for a live range that is defined by
/// the same instruction (Slot_Register or Slot_EarlyClobber), but isn't
/// used anywhere.
Slot_Dead,
Slot_Count
};
PointerIntPair<IndexListEntry*, 2, unsigned> lie;
SlotIndex(IndexListEntry *entry, unsigned slot)
: lie(entry, slot) {}
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();
}
unsigned getIndex() const {
return listEntry()->getIndex() | getSlot();
}
/// Returns the slot for this SlotIndex.
Slot getSlot() const {
return static_cast<Slot>(lie.getInt());
}
public:
enum {
/// The default distance between instructions as returned by distance().
/// This may vary as instructions are inserted and removed.
InstrDist = 4 * Slot_Count
};
/// Construct an invalid index.
SlotIndex() : lie(nullptr, 0) {}
// Construct a new slot index from the given one, and set the slot.
SlotIndex(const SlotIndex &li, Slot s) : lie(li.listEntry(), unsigned(s)) {
assert(lie.getPointer() != nullptr &&
"Attempt to construct index with 0 pointer.");
}
/// Returns true if this is a valid index. Invalid indicies do
/// not point into an index table, and cannot be compared.
bool isValid() const {
return lie.getPointer();
}
/// Return true for a valid index.
LLVM_EXPLICIT operator bool() const { return isValid(); }
/// Print this index to the given raw_ostream.
void print(raw_ostream &os) const;
/// Dump this index to stderr.
void dump() const;
/// Compare two SlotIndex objects for equality.
bool operator==(SlotIndex other) const {
return lie == other.lie;
}
/// Compare two SlotIndex objects for inequality.
bool operator!=(SlotIndex other) const {
return lie != other.lie;
}
/// Compare two SlotIndex objects. Return true if the first index
/// is strictly lower than the second.
bool operator<(SlotIndex other) const {
return getIndex() < other.getIndex();
}
/// Compare two SlotIndex objects. Return true if the first index
/// is lower than, or equal to, the second.
bool operator<=(SlotIndex other) const {
return getIndex() <= other.getIndex();
}
/// Compare two SlotIndex objects. Return true if the first index
/// is greater than the second.
bool operator>(SlotIndex other) const {
return getIndex() > other.getIndex();
}
/// Compare two SlotIndex objects. Return true if the first index
/// is greater than, or equal to, the second.
bool operator>=(SlotIndex other) const {
return getIndex() >= other.getIndex();
}
/// isSameInstr - Return true if A and B refer to the same instruction.
static bool isSameInstr(SlotIndex A, SlotIndex B) {
return A.lie.getPointer() == B.lie.getPointer();
}
/// isEarlierInstr - Return true if A refers to an instruction earlier than
/// B. This is equivalent to A < B && !isSameInstr(A, B).
static bool isEarlierInstr(SlotIndex A, SlotIndex B) {
return A.listEntry()->getIndex() < B.listEntry()->getIndex();
}
/// Return the distance from this index to the given one.
int distance(SlotIndex other) const {
return other.getIndex() - getIndex();
}
/// Return the scaled distance from this index to the given one, where all
/// slots on the same instruction have zero distance.
int getInstrDistance(SlotIndex other) const {
return (other.listEntry()->getIndex() - listEntry()->getIndex())
/ Slot_Count;
}
/// isBlock - Returns true if this is a block boundary slot.
bool isBlock() const { return getSlot() == Slot_Block; }
/// isEarlyClobber - Returns true if this is an early-clobber slot.
bool isEarlyClobber() const { return getSlot() == Slot_EarlyClobber; }
/// isRegister - Returns true if this is a normal register use/def slot.
/// Note that early-clobber slots may also be used for uses and defs.
bool isRegister() const { return getSlot() == Slot_Register; }
/// isDead - Returns true if this is a dead def kill slot.
bool isDead() const { return getSlot() == Slot_Dead; }
/// Returns the base index for associated with this index. The base index
/// is the one associated with the Slot_Block slot for the instruction
/// pointed to by this index.
SlotIndex getBaseIndex() const {
return SlotIndex(listEntry(), Slot_Block);
}
/// Returns the boundary index for associated with this index. The boundary
/// index is the one associated with the Slot_Block slot for the instruction
/// pointed to by this index.
SlotIndex getBoundaryIndex() const {
return SlotIndex(listEntry(), Slot_Dead);
}
/// Returns the register use/def slot in the current instruction for a
/// normal or early-clobber def.
SlotIndex getRegSlot(bool EC = false) const {
return SlotIndex(listEntry(), EC ? Slot_EarlyClobber : Slot_Register);
}
/// Returns the dead def kill slot for the current instruction.
SlotIndex getDeadSlot() const {
return SlotIndex(listEntry(), Slot_Dead);
}
/// Returns the next slot in the index list. This could be either the
/// next slot for the instruction pointed to by this index or, if this
/// index is a STORE, the first slot for the next instruction.
/// WARNING: This method is considerably more expensive than the methods
/// that return specific slots (getUseIndex(), etc). If you can - please
/// use one of those methods.
SlotIndex getNextSlot() const {
Slot s = getSlot();
if (s == Slot_Dead) {
return SlotIndex(listEntry()->getNextNode(), Slot_Block);
}
return SlotIndex(listEntry(), s + 1);
}
/// Returns the next index. This is the index corresponding to the this
/// index's slot, but for the next instruction.
SlotIndex getNextIndex() const {
return SlotIndex(listEntry()->getNextNode(), getSlot());
}
/// Returns the previous slot in the index list. This could be either the
/// previous slot for the instruction pointed to by this index or, if this
/// index is a Slot_Block, the last slot for the previous instruction.
/// WARNING: This method is considerably more expensive than the methods
/// that return specific slots (getUseIndex(), etc). If you can - please
/// use one of those methods.
SlotIndex getPrevSlot() const {
Slot s = getSlot();
if (s == Slot_Block) {
return SlotIndex(listEntry()->getPrevNode(), Slot_Dead);
}
return SlotIndex(listEntry(), s - 1);
}
/// Returns the previous index. This is the index corresponding to this
/// index's slot, but for the previous instruction.
SlotIndex getPrevIndex() const {
return SlotIndex(listEntry()->getPrevNode(), getSlot());
}
};
template <> struct isPodLike<SlotIndex> { static const bool value = true; };
inline raw_ostream& operator<<(raw_ostream &os, SlotIndex li) {
li.print(os);
return os;
}
typedef std::pair<SlotIndex, MachineBasicBlock*> IdxMBBPair;
inline bool operator<(SlotIndex V, const IdxMBBPair &IM) {
return V < IM.first;
}
inline bool operator<(const IdxMBBPair &IM, SlotIndex V) {
return IM.first < V;
}
struct Idx2MBBCompare {
bool operator()(const IdxMBBPair &LHS, const IdxMBBPair &RHS) const {
return LHS.first < RHS.first;
}
};
/// SlotIndexes pass.
///
/// This pass assigns indexes to each instruction.
class SlotIndexes : public MachineFunctionPass {
private:
typedef ilist<IndexListEntry> IndexList;
IndexList indexList;
#ifdef EXPENSIVE_CHECKS
IndexList graveyardList;
#endif // EXPENSIVE_CHECKS
MachineFunction *mf;
typedef DenseMap<const MachineInstr*, SlotIndex> Mi2IndexMap;
Mi2IndexMap mi2iMap;
/// MBBRanges - Map MBB number to (start, stop) indexes.
SmallVector<std::pair<SlotIndex, SlotIndex>, 8> MBBRanges;
/// Idx2MBBMap - Sorted list of pairs of index of first instruction
/// and MBB id.
SmallVector<IdxMBBPair, 8> idx2MBBMap;
// IndexListEntry allocator.
BumpPtrAllocator ileAllocator;
IndexListEntry* createEntry(MachineInstr *mi, unsigned index) {
IndexListEntry *entry =
static_cast<IndexListEntry*>(
ileAllocator.Allocate(sizeof(IndexListEntry),
alignOf<IndexListEntry>()));
new (entry) IndexListEntry(mi, index);
return entry;
}
/// Renumber locally after inserting curItr.
void renumberIndexes(IndexList::iterator curItr);
public:
static char ID;
SlotIndexes() : MachineFunctionPass(ID) {
initializeSlotIndexesPass(*PassRegistry::getPassRegistry());
}
void getAnalysisUsage(AnalysisUsage &au) const override;
void releaseMemory() override;
bool runOnMachineFunction(MachineFunction &fn) override;
/// Dump the indexes.
void dump() const;
/// 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 SlotIndex(&indexList.front(), 0);
}
/// Returns the base index of the last slot in this analysis.
SlotIndex getLastIndex() {
return SlotIndex(&indexList.back(), 0);
}
/// Returns true if the given machine instr is mapped to an index,
/// otherwise returns false.
bool hasIndex(const MachineInstr *instr) const {
return mi2iMap.count(instr);
}
/// Returns the base index for the given instruction.
SlotIndex getInstructionIndex(const MachineInstr *MI) const {
// Instructions inside a bundle have the same number as the bundle itself.
Mi2IndexMap::const_iterator itr = mi2iMap.find(getBundleStart(MI));
assert(itr != mi2iMap.end() && "Instruction not found in maps.");
return itr->second;
}
/// Returns the instruction for the given index, or null if the given
/// index has no instruction associated with it.
MachineInstr* getInstructionFromIndex(SlotIndex index) const {
return index.isValid() ? index.listEntry()->getInstr() : nullptr;
}
/// 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 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();
assert(MBB && "MI must be inserted inna basic block");
MachineBasicBlock::const_iterator I = MI, B = MBB->begin();
for (;;) {
if (I == B)
return getMBBStartIdx(MBB);
--I;
Mi2IndexMap::const_iterator MapItr = mi2iMap.find(I);
if (MapItr != mi2iMap.end())
return MapItr->second;
}
}
/// getIndexAfter - Returns the index of the first indexed instruction
/// after MI, or the end index of its basic block.
/// MI is not required to have an index.
SlotIndex getIndexAfter(const MachineInstr *MI) const {
const MachineBasicBlock *MBB = MI->getParent();
assert(MBB && "MI must be inserted inna basic block");
MachineBasicBlock::const_iterator I = MI, E = MBB->end();
for (;;) {
++I;
if (I == E)
return getMBBEndIdx(MBB);
Mi2IndexMap::const_iterator MapItr = mi2iMap.find(I);
if (MapItr != mi2iMap.end())
return MapItr->second;
}
}
/// Return the (start,end) range of the given basic block number.
const std::pair<SlotIndex, SlotIndex> &
getMBBRange(unsigned Num) const {
return MBBRanges[Num];
}
/// Return the (start,end) range of the given basic block.
const std::pair<SlotIndex, SlotIndex> &
getMBBRange(const MachineBasicBlock *MBB) const {
return getMBBRange(MBB->getNumber());
}
/// Returns the first index in the given basic block number.
SlotIndex getMBBStartIdx(unsigned Num) const {
return getMBBRange(Num).first;
}
/// Returns the first index in the given basic block.
SlotIndex getMBBStartIdx(const MachineBasicBlock *mbb) const {
return getMBBRange(mbb).first;
}
/// Returns the last index in the given basic block number.
SlotIndex getMBBEndIdx(unsigned Num) const {
return getMBBRange(Num).second;
}
/// Returns the last index in the given basic block.
SlotIndex getMBBEndIdx(const MachineBasicBlock *mbb) const {
return getMBBRange(mbb).second;
}
/// Returns the basic block which the given index falls in.
MachineBasicBlock* getMBBFromIndex(SlotIndex index) const {
if (MachineInstr *MI = getInstructionFromIndex(index))
return MI->getParent();
SmallVectorImpl<IdxMBBPair>::const_iterator I =
std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), index);
// Take the pair containing the index
SmallVectorImpl<IdxMBBPair>::const_iterator J =
((I != idx2MBBMap.end() && I->first > index) ||
(I == idx2MBBMap.end() && idx2MBBMap.size()>0)) ? (I-1): I;
assert(J != idx2MBBMap.end() && J->first <= index &&
index < getMBBEndIdx(J->second) &&
"index does not correspond to an MBB");
return J->second;
}
bool findLiveInMBBs(SlotIndex start, SlotIndex end,
SmallVectorImpl<MachineBasicBlock*> &mbbs) const {
SmallVectorImpl<IdxMBBPair>::const_iterator itr =
std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), start);
bool resVal = false;
while (itr != idx2MBBMap.end()) {
if (itr->first >= end)
break;
mbbs.push_back(itr->second);
resVal = true;
++itr;
}
return resVal;
}
/// Returns the MBB covering the given range, or null if the range covers
/// more than one basic block.
MachineBasicBlock* getMBBCoveringRange(SlotIndex start, SlotIndex end) const {
assert(start < end && "Backwards ranges not allowed.");
SmallVectorImpl<IdxMBBPair>::const_iterator itr =
std::lower_bound(idx2MBBMap.begin(), idx2MBBMap.end(), start);
if (itr == idx2MBBMap.end()) {
itr = std::prev(itr);
return itr->second;
}
// Check that we don't cross the boundary into this block.
if (itr->first < end)
return nullptr;
itr = std::prev(itr);
if (itr->first <= start)
return itr->second;
return nullptr;
}
/// Insert the given machine instruction into the mapping. Returns the
/// assigned index.
/// If Late is set and there are null indexes between mi's neighboring
/// instructions, create the new index after the null indexes instead of
/// before them.
SlotIndex insertMachineInstrInMaps(MachineInstr *mi, bool Late = false) {
assert(!mi->isInsideBundle() &&
"Instructions inside bundles should use bundle start's slot.");
assert(mi2iMap.find(mi) == mi2iMap.end() && "Instr already indexed.");
// Numbering DBG_VALUE instructions could cause code generation to be
// affected by debug information.
assert(!mi->isDebugValue() && "Cannot number DBG_VALUE instructions.");
assert(mi->getParent() != nullptr && "Instr must be added to function.");
// Get the entries where mi should be inserted.
IndexList::iterator prevItr, nextItr;
if (Late) {
// Insert mi's index immediately before the following instruction.
nextItr = getIndexAfter(mi).listEntry();
prevItr = std::prev(nextItr);
} else {
// Insert mi's index immediately after the preceding instruction.
prevItr = getIndexBefore(mi).listEntry();
nextItr = std::next(prevItr);
}
// Get a number for the new instr, or 0 if there's no room currently.
// In the latter case we'll force a renumber later.
unsigned dist = ((nextItr->getIndex() - prevItr->getIndex())/2) & ~3u;
unsigned newNumber = prevItr->getIndex() + dist;
// Insert a new list entry for mi.
IndexList::iterator newItr =
indexList.insert(nextItr, createEntry(mi, newNumber));
// Renumber locally if we need to.
if (dist == 0)
renumberIndexes(newItr);
SlotIndex newIndex(&*newItr, SlotIndex::Slot_Block);
mi2iMap.insert(std::make_pair(mi, newIndex));
return newIndex;
}
/// Remove the given machine instruction from the mapping.
void removeMachineInstrFromMaps(MachineInstr *mi) {
// remove index -> MachineInstr and
// MachineInstr -> index mappings
Mi2IndexMap::iterator mi2iItr = mi2iMap.find(mi);
if (mi2iItr != mi2iMap.end()) {
IndexListEntry *miEntry(mi2iItr->second.listEntry());
assert(miEntry->getInstr() == mi && "Instruction indexes broken.");
// FIXME: Eventually we want to actually delete these indexes.
miEntry->setInstr(nullptr);
mi2iMap.erase(mi2iItr);
}
}
/// ReplaceMachineInstrInMaps - Replacing a machine instr with a new one in
/// maps used by register allocator.
void replaceMachineInstrInMaps(MachineInstr *mi, MachineInstr *newMI) {
Mi2IndexMap::iterator mi2iItr = mi2iMap.find(mi);
if (mi2iItr == mi2iMap.end())
return;
SlotIndex replaceBaseIndex = mi2iItr->second;
IndexListEntry *miEntry(replaceBaseIndex.listEntry());
assert(miEntry->getInstr() == mi &&
"Mismatched instruction in index tables.");
miEntry->setInstr(newMI);
mi2iMap.erase(mi2iItr);
mi2iMap.insert(std::make_pair(newMI, replaceBaseIndex));
}
/// Add the given MachineBasicBlock into the maps.
void insertMBBInMaps(MachineBasicBlock *mbb) {
MachineFunction::iterator nextMBB =
std::next(MachineFunction::iterator(mbb));
IndexListEntry *startEntry = nullptr;
IndexListEntry *endEntry = nullptr;
IndexList::iterator newItr;
if (nextMBB == mbb->getParent()->end()) {
startEntry = &indexList.back();
endEntry = createEntry(nullptr, 0);
newItr = indexList.insertAfter(startEntry, endEntry);
} else {
startEntry = createEntry(nullptr, 0);
endEntry = getMBBStartIdx(nextMBB).listEntry();
newItr = indexList.insert(endEntry, startEntry);
}
SlotIndex startIdx(startEntry, 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(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 <>
struct IntervalMapInfo<SlotIndex> : IntervalMapHalfOpenInfo<SlotIndex> {
};
}
#endif // LLVM_CODEGEN_SLOTINDEXES_H