llvm-6502/lib/CodeGen/SlotIndexes.cpp
Jakob Stoklund Olesen 979869c28e Renumber slot indexes locally when possible.
Initially, slot indexes are quad-spaced. There is room for inserting up to 3
new instructions between the original instructions.

When we run out of indexes between two instructions, renumber locally using
double-spaced indexes. The original quad-spacing means that we catch up quickly,
and we only have to renumber a handful of instructions to get a monotonic
sequence. This is much faster than renumbering the whole function as we did
before.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127023 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-04 19:43:38 +00:00

182 lines
5.4 KiB
C++

//===-- SlotIndexes.cpp - Slot Indexes Pass ------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "slotindexes"
#include "llvm/CodeGen/SlotIndexes.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetInstrInfo.h"
using namespace llvm;
char SlotIndexes::ID = 0;
INITIALIZE_PASS(SlotIndexes, "slotindexes",
"Slot index numbering", false, false)
STATISTIC(NumLocalRenum, "Number of local renumberings");
STATISTIC(NumGlobalRenum, "Number of global renumberings");
void SlotIndexes::getAnalysisUsage(AnalysisUsage &au) const {
au.setPreservesAll();
MachineFunctionPass::getAnalysisUsage(au);
}
void SlotIndexes::releaseMemory() {
mi2iMap.clear();
mbb2IdxMap.clear();
idx2MBBMap.clear();
clearList();
}
bool SlotIndexes::runOnMachineFunction(MachineFunction &fn) {
// Compute numbering as follows:
// Grab an iterator to the start of the index list.
// Iterate over all MBBs, and within each MBB all MIs, keeping the MI
// iterator in lock-step (though skipping it over indexes which have
// null pointers in the instruction field).
// At each iteration assert that the instruction pointed to in the index
// is the same one pointed to by the MI iterator. This
// FIXME: This can be simplified. The mi2iMap_, Idx2MBBMap, etc. should
// only need to be set up once after the first numbering is computed.
mf = &fn;
initList();
// Check that the list contains only the sentinal.
assert(indexListHead->getNext() == 0 &&
"Index list non-empty at initial numbering?");
assert(idx2MBBMap.empty() &&
"Index -> MBB mapping non-empty at initial numbering?");
assert(mbb2IdxMap.empty() &&
"MBB -> Index mapping non-empty at initial numbering?");
assert(mi2iMap.empty() &&
"MachineInstr -> Index mapping non-empty at initial numbering?");
functionSize = 0;
unsigned index = 0;
push_back(createEntry(0, index));
// Iterate over the function.
for (MachineFunction::iterator mbbItr = mf->begin(), mbbEnd = mf->end();
mbbItr != mbbEnd; ++mbbItr) {
MachineBasicBlock *mbb = &*mbbItr;
// Insert an index for the MBB start.
SlotIndex blockStartIndex(back(), SlotIndex::LOAD);
for (MachineBasicBlock::iterator miItr = mbb->begin(), miEnd = mbb->end();
miItr != miEnd; ++miItr) {
MachineInstr *mi = miItr;
if (mi->isDebugValue())
continue;
// Insert a store index for the instr.
push_back(createEntry(mi, index += SlotIndex::InstrDist));
// Save this base index in the maps.
mi2iMap.insert(std::make_pair(mi, SlotIndex(back(), SlotIndex::LOAD)));
++functionSize;
}
// We insert one blank instructions between basic blocks.
push_back(createEntry(0, index += SlotIndex::InstrDist));
SlotIndex blockEndIndex(back(), SlotIndex::LOAD);
mbb2IdxMap.insert(
std::make_pair(mbb, std::make_pair(blockStartIndex, blockEndIndex)));
idx2MBBMap.push_back(IdxMBBPair(blockStartIndex, mbb));
}
// Sort the Idx2MBBMap
std::sort(idx2MBBMap.begin(), idx2MBBMap.end(), Idx2MBBCompare());
DEBUG(dump());
// And we're done!
return false;
}
void SlotIndexes::renumberIndexes() {
// Renumber updates the index of every element of the index list.
DEBUG(dbgs() << "\n*** Renumbering SlotIndexes ***\n");
++NumGlobalRenum;
unsigned index = 0;
for (IndexListEntry *curEntry = front(); curEntry != getTail();
curEntry = curEntry->getNext()) {
curEntry->setIndex(index);
index += SlotIndex::InstrDist;
}
}
// Renumber indexes locally after curEntry was inserted, but failed to get a new
// index.
void SlotIndexes::renumberIndexes(IndexListEntry *curEntry) {
// Number indexes with half the default spacing so we can catch up quickly.
const unsigned Space = SlotIndex::InstrDist/2;
assert((Space & 3) == 0 && "InstrDist must be a multiple of 2*NUM");
IndexListEntry *start = curEntry->getPrev();
unsigned index = start->getIndex();
IndexListEntry *tail = getTail();
do {
curEntry->setIndex(index += Space);
curEntry = curEntry->getNext();
// If the next index is bigger, we have caught up.
} while (curEntry != tail && curEntry->getIndex() <= index);
DEBUG(dbgs() << "\n*** Renumbered SlotIndexes " << start->getIndex() << '-'
<< index << " ***\n");
++NumLocalRenum;
}
void SlotIndexes::dump() const {
for (const IndexListEntry *itr = front(); itr != getTail();
itr = itr->getNext()) {
dbgs() << itr->getIndex() << " ";
if (itr->getInstr() != 0) {
dbgs() << *itr->getInstr();
} else {
dbgs() << "\n";
}
}
for (MBB2IdxMap::const_iterator itr = mbb2IdxMap.begin();
itr != mbb2IdxMap.end(); ++itr) {
dbgs() << "MBB " << itr->first->getNumber() << " (" << itr->first << ") - ["
<< itr->second.first << ", " << itr->second.second << "]\n";
}
}
// Print a SlotIndex to a raw_ostream.
void SlotIndex::print(raw_ostream &os) const {
if (isValid())
os << entry().getIndex() << "LudS"[getSlot()];
else
os << "invalid";
}
// Dump a SlotIndex to stderr.
void SlotIndex::dump() const {
print(dbgs());
dbgs() << "\n";
}