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llvm-mirror/lib/CodeGen/LiveStacks.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

88 lines
3.0 KiB
C++

//===-- LiveStacks.cpp - Live Stack Slot Analysis -------------------------===//
//
// 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 implements the live stack slot analysis pass. It is analogous to
// live interval analysis except it's analyzing liveness of stack slots rather
// than registers.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/LiveStacks.h"
#include "llvm/CodeGen/LiveIntervals.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DEBUG_TYPE "livestacks"
char LiveStacks::ID = 0;
INITIALIZE_PASS_BEGIN(LiveStacks, DEBUG_TYPE,
"Live Stack Slot Analysis", false, false)
INITIALIZE_PASS_DEPENDENCY(SlotIndexes)
INITIALIZE_PASS_END(LiveStacks, DEBUG_TYPE,
"Live Stack Slot Analysis", false, false)
char &llvm::LiveStacksID = LiveStacks::ID;
void LiveStacks::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addPreserved<SlotIndexes>();
AU.addRequiredTransitive<SlotIndexes>();
MachineFunctionPass::getAnalysisUsage(AU);
}
void LiveStacks::releaseMemory() {
// Release VNInfo memory regions, VNInfo objects don't need to be dtor'd.
VNInfoAllocator.Reset();
S2IMap.clear();
S2RCMap.clear();
}
bool LiveStacks::runOnMachineFunction(MachineFunction &MF) {
TRI = MF.getSubtarget().getRegisterInfo();
// FIXME: No analysis is being done right now. We are relying on the
// register allocators to provide the information.
return false;
}
LiveInterval &
LiveStacks::getOrCreateInterval(int Slot, const TargetRegisterClass *RC) {
assert(Slot >= 0 && "Spill slot indice must be >= 0");
SS2IntervalMap::iterator I = S2IMap.find(Slot);
if (I == S2IMap.end()) {
I = S2IMap.emplace(std::piecewise_construct, std::forward_as_tuple(Slot),
std::forward_as_tuple(
TargetRegisterInfo::index2StackSlot(Slot), 0.0F))
.first;
S2RCMap.insert(std::make_pair(Slot, RC));
} else {
// Use the largest common subclass register class.
const TargetRegisterClass *OldRC = S2RCMap[Slot];
S2RCMap[Slot] = TRI->getCommonSubClass(OldRC, RC);
}
return I->second;
}
/// print - Implement the dump method.
void LiveStacks::print(raw_ostream &OS, const Module*) const {
OS << "********** INTERVALS **********\n";
for (const_iterator I = begin(), E = end(); I != E; ++I) {
I->second.print(OS);
int Slot = I->first;
const TargetRegisterClass *RC = getIntervalRegClass(Slot);
if (RC)
OS << " [" << TRI->getRegClassName(RC) << "]\n";
else
OS << " [Unknown]\n";
}
}