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//===- IntervalPartition.cpp - Interval Partition module code -------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file contains the definition of the IntervalPartition class, which
// calculates and represent the interval partition of a function.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/IntervalPartition.h"
#include "llvm/Analysis/Interval.h"
#include "llvm/Analysis/IntervalIterator.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include <cassert>
#include <utility>
using namespace llvm;
char IntervalPartition::ID = 0;
IntervalPartition::IntervalPartition() : FunctionPass(ID) {
initializeIntervalPartitionPass(*PassRegistry::getPassRegistry());
}
INITIALIZE_PASS(IntervalPartition, "intervals",
"Interval Partition Construction", true, true)
//===----------------------------------------------------------------------===//
// IntervalPartition Implementation
//===----------------------------------------------------------------------===//
// releaseMemory - Reset state back to before function was analyzed
void IntervalPartition::releaseMemory() {
for (Interval *I : Intervals)
delete I;
IntervalMap.clear();
Intervals.clear();
RootInterval = nullptr;
}
void IntervalPartition::print(raw_ostream &O, const Module*) const {
for (const Interval *I : Intervals)
I->print(O);
}
// addIntervalToPartition - Add an interval to the internal list of intervals,
// and then add mappings from all of the basic blocks in the interval to the
// interval itself (in the IntervalMap).
void IntervalPartition::addIntervalToPartition(Interval *I) {
Intervals.push_back(I);
// Add mappings for all of the basic blocks in I to the IntervalPartition
for (Interval::node_iterator It = I->Nodes.begin(), End = I->Nodes.end();
It != End; ++It)
IntervalMap.insert(std::make_pair(*It, I));
}
// updatePredecessors - Interval generation only sets the successor fields of
// the interval data structures. After interval generation is complete,
// run through all of the intervals and propagate successor info as
// predecessor info.
void IntervalPartition::updatePredecessors(Interval *Int) {
BasicBlock *Header = Int->getHeaderNode();
for (BasicBlock *Successor : Int->Successors)
getBlockInterval(Successor)->Predecessors.push_back(Header);
}
// IntervalPartition ctor - Build the first level interval partition for the
// specified function...
bool IntervalPartition::runOnFunction(Function &F) {
// Pass false to intervals_begin because we take ownership of it's memory
function_interval_iterator I = intervals_begin(&F, false);
assert(I != intervals_end(&F) && "No intervals in function!?!?!");
addIntervalToPartition(RootInterval = *I);
++I; // After the first one...
// Add the rest of the intervals to the partition.
for (function_interval_iterator E = intervals_end(&F); I != E; ++I)
addIntervalToPartition(*I);
// Now that we know all of the successor information, propagate this to the
// predecessors for each block.
for (Interval *I : Intervals)
updatePredecessors(I);
return false;
}
// IntervalPartition ctor - Build a reduced interval partition from an
// existing interval graph. This takes an additional boolean parameter to
// distinguish it from a copy constructor. Always pass in false for now.
IntervalPartition::IntervalPartition(IntervalPartition &IP, bool)
: FunctionPass(ID) {
assert(IP.getRootInterval() && "Cannot operate on empty IntervalPartitions!");
// Pass false to intervals_begin because we take ownership of it's memory
interval_part_interval_iterator I = intervals_begin(IP, false);
assert(I != intervals_end(IP) && "No intervals in interval partition!?!?!");
addIntervalToPartition(RootInterval = *I);
++I; // After the first one...
// Add the rest of the intervals to the partition.
for (interval_part_interval_iterator E = intervals_end(IP); I != E; ++I)
addIntervalToPartition(*I);
// Now that we know all of the successor information, propagate this to the
// predecessors for each block.
for (Interval *I : Intervals)
updatePredecessors(I);
}