ff5718f042
This patch is the result of static analysis identifying a number of memory leaks. The leaks are all benign as they are a result of not deallocating memory in the desctructor. The fix still has value as it removes false positives in the static analysis.
465 lines
14 KiB
C++
465 lines
14 KiB
C++
/*
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* Copyright (c) 2002-2005 The Regents of The University of Michigan
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* Copyright (c) 2010 Advanced Micro Devices, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Erik Hallnor
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* Dave Greene
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*/
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/**
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* @file
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* Miss Status and Handling Register (MSHR) definitions.
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*/
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#include <algorithm>
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#include <cassert>
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#include <string>
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#include <vector>
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#include "base/misc.hh"
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#include "base/types.hh"
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#include "debug/Cache.hh"
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#include "mem/cache/cache.hh"
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#include "mem/cache/mshr.hh"
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#include "sim/core.hh"
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using namespace std;
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MSHR::MSHR()
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{
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inService = false;
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ntargets = 0;
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threadNum = InvalidThreadID;
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targets = new TargetList();
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deferredTargets = new TargetList();
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}
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MSHR::TargetList::TargetList()
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: needsExclusive(false), hasUpgrade(false)
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{}
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inline void
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MSHR::TargetList::add(PacketPtr pkt, Tick readyTime,
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Counter order, Target::Source source, bool markPending)
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{
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if (source != Target::FromSnoop) {
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if (pkt->needsExclusive()) {
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needsExclusive = true;
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}
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// StoreCondReq is effectively an upgrade if it's in an MSHR
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// since it would have been failed already if we didn't have a
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// read-only copy
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if (pkt->isUpgrade() || pkt->cmd == MemCmd::StoreCondReq) {
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hasUpgrade = true;
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}
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}
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if (markPending) {
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MSHR *mshr = dynamic_cast<MSHR*>(pkt->senderState);
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if (mshr != NULL) {
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assert(!mshr->downstreamPending);
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mshr->downstreamPending = true;
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}
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}
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push_back(Target(pkt, readyTime, order, source, markPending));
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}
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static void
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replaceUpgrade(PacketPtr pkt)
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{
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if (pkt->cmd == MemCmd::UpgradeReq) {
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pkt->cmd = MemCmd::ReadExReq;
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DPRINTF(Cache, "Replacing UpgradeReq with ReadExReq\n");
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} else if (pkt->cmd == MemCmd::SCUpgradeReq) {
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pkt->cmd = MemCmd::SCUpgradeFailReq;
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DPRINTF(Cache, "Replacing SCUpgradeReq with SCUpgradeFailReq\n");
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} else if (pkt->cmd == MemCmd::StoreCondReq) {
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pkt->cmd = MemCmd::StoreCondFailReq;
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DPRINTF(Cache, "Replacing StoreCondReq with StoreCondFailReq\n");
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}
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}
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void
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MSHR::TargetList::replaceUpgrades()
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{
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if (!hasUpgrade)
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return;
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Iterator end_i = end();
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for (Iterator i = begin(); i != end_i; ++i) {
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replaceUpgrade(i->pkt);
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}
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hasUpgrade = false;
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}
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void
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MSHR::TargetList::clearDownstreamPending()
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{
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Iterator end_i = end();
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for (Iterator i = begin(); i != end_i; ++i) {
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if (i->markedPending) {
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MSHR *mshr = dynamic_cast<MSHR*>(i->pkt->senderState);
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if (mshr != NULL) {
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mshr->clearDownstreamPending();
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}
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}
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}
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}
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bool
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MSHR::TargetList::checkFunctional(PacketPtr pkt)
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{
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Iterator end_i = end();
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for (Iterator i = begin(); i != end_i; ++i) {
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if (pkt->checkFunctional(i->pkt)) {
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return true;
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}
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}
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return false;
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}
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void
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MSHR::TargetList::
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print(std::ostream &os, int verbosity, const std::string &prefix) const
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{
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ConstIterator end_i = end();
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for (ConstIterator i = begin(); i != end_i; ++i) {
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const char *s;
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switch (i->source) {
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case Target::FromCPU:
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s = "FromCPU";
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break;
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case Target::FromSnoop:
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s = "FromSnoop";
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break;
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case Target::FromPrefetcher:
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s = "FromPrefetcher";
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break;
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default:
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s = "";
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break;
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}
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ccprintf(os, "%s%s: ", prefix, s);
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i->pkt->print(os, verbosity, "");
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}
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}
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void
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MSHR::allocate(Addr _addr, int _size, PacketPtr target,
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Tick whenReady, Counter _order)
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{
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addr = _addr;
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size = _size;
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readyTime = whenReady;
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order = _order;
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assert(target);
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isForward = false;
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_isUncacheable = target->req->isUncacheable();
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inService = false;
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downstreamPending = false;
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threadNum = 0;
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ntargets = 1;
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assert(targets->isReset());
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// Don't know of a case where we would allocate a new MSHR for a
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// snoop (mem-side request), so set source according to request here
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Target::Source source = (target->cmd == MemCmd::HardPFReq) ?
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Target::FromPrefetcher : Target::FromCPU;
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targets->add(target, whenReady, _order, source, true);
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assert(deferredTargets->isReset());
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data = NULL;
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}
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void
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MSHR::clearDownstreamPending()
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{
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assert(downstreamPending);
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downstreamPending = false;
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// recursively clear flag on any MSHRs we will be forwarding
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// responses to
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targets->clearDownstreamPending();
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}
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bool
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MSHR::markInService(PacketPtr pkt)
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{
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assert(!inService);
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if (isForwardNoResponse()) {
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// we just forwarded the request packet & don't expect a
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// response, so get rid of it
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assert(getNumTargets() == 1);
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popTarget();
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return true;
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}
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inService = true;
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pendingDirty = (targets->needsExclusive ||
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(!pkt->sharedAsserted() && pkt->memInhibitAsserted()));
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postInvalidate = postDowngrade = false;
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if (!downstreamPending) {
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// let upstream caches know that the request has made it to a
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// level where it's going to get a response
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targets->clearDownstreamPending();
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}
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return false;
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}
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void
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MSHR::deallocate()
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{
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assert(targets->empty());
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targets->resetFlags();
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assert(deferredTargets->isReset());
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assert(ntargets == 0);
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inService = false;
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}
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/*
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* Adds a target to an MSHR
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*/
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void
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MSHR::allocateTarget(PacketPtr pkt, Tick whenReady, Counter _order)
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{
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// if there's a request already in service for this MSHR, we will
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// have to defer the new target until after the response if any of
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// the following are true:
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// - there are other targets already deferred
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// - there's a pending invalidate to be applied after the response
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// comes back (but before this target is processed)
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// - this target requires an exclusive block and either we're not
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// getting an exclusive block back or we have already snooped
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// another read request that will downgrade our exclusive block
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// to shared
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// assume we'd never issue a prefetch when we've got an
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// outstanding miss
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assert(pkt->cmd != MemCmd::HardPFReq);
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if (inService &&
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(!deferredTargets->empty() || hasPostInvalidate() ||
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(pkt->needsExclusive() &&
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(!isPendingDirty() || hasPostDowngrade() || isForward)))) {
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// need to put on deferred list
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if (hasPostInvalidate())
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replaceUpgrade(pkt);
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deferredTargets->add(pkt, whenReady, _order, Target::FromCPU, true);
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} else {
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// No request outstanding, or still OK to append to
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// outstanding request: append to regular target list. Only
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// mark pending if current request hasn't been issued yet
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// (isn't in service).
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targets->add(pkt, whenReady, _order, Target::FromCPU, !inService);
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}
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++ntargets;
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}
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bool
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MSHR::handleSnoop(PacketPtr pkt, Counter _order)
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{
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if (!inService || (pkt->isExpressSnoop() && downstreamPending)) {
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// Request has not been issued yet, or it's been issued
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// locally but is buffered unissued at some downstream cache
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// which is forwarding us this snoop. Either way, the packet
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// we're snooping logically precedes this MSHR's request, so
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// the snoop has no impact on the MSHR, but must be processed
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// in the standard way by the cache. The only exception is
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// that if we're an L2+ cache buffering an UpgradeReq from a
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// higher-level cache, and the snoop is invalidating, then our
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// buffered upgrades must be converted to read exclusives,
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// since the upper-level cache no longer has a valid copy.
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// That is, even though the upper-level cache got out on its
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// local bus first, some other invalidating transaction
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// reached the global bus before the upgrade did.
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if (pkt->needsExclusive()) {
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targets->replaceUpgrades();
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deferredTargets->replaceUpgrades();
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}
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return false;
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}
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// From here on down, the request issued by this MSHR logically
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// precedes the request we're snooping.
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if (pkt->needsExclusive()) {
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// snooped request still precedes the re-request we'll have to
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// issue for deferred targets, if any...
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deferredTargets->replaceUpgrades();
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}
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if (hasPostInvalidate()) {
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// a prior snoop has already appended an invalidation, so
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// logically we don't have the block anymore; no need for
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// further snooping.
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return true;
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}
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if (isPendingDirty() || pkt->isInvalidate()) {
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// We need to save and replay the packet in two cases:
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// 1. We're awaiting an exclusive copy, so ownership is pending,
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// and we need to respond after we receive data.
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// 2. It's an invalidation (e.g., UpgradeReq), and we need
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// to forward the snoop up the hierarchy after the current
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// transaction completes.
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// Actual target device (typ. a memory) will delete the
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// packet on reception, so we need to save a copy here.
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PacketPtr cp_pkt = new Packet(pkt, true);
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targets->add(cp_pkt, curTick(), _order, Target::FromSnoop,
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downstreamPending && targets->needsExclusive);
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++ntargets;
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if (isPendingDirty()) {
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pkt->assertMemInhibit();
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pkt->setSupplyExclusive();
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}
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if (pkt->needsExclusive()) {
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// This transaction will take away our pending copy
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postInvalidate = true;
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}
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}
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if (!pkt->needsExclusive()) {
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// This transaction will get a read-shared copy, downgrading
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// our copy if we had an exclusive one
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postDowngrade = true;
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pkt->assertShared();
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}
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return true;
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}
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bool
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MSHR::promoteDeferredTargets()
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{
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assert(targets->empty());
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if (deferredTargets->empty()) {
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return false;
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}
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// swap targets & deferredTargets lists
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TargetList *tmp = targets;
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targets = deferredTargets;
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deferredTargets = tmp;
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assert(targets->size() == ntargets);
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// clear deferredTargets flags
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deferredTargets->resetFlags();
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order = targets->front().order;
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readyTime = std::max(curTick(), targets->front().readyTime);
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return true;
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}
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void
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MSHR::handleFill(Packet *pkt, CacheBlk *blk)
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{
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if (!pkt->sharedAsserted()
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&& !(hasPostInvalidate() || hasPostDowngrade())
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&& deferredTargets->needsExclusive) {
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// We got an exclusive response, but we have deferred targets
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// which are waiting to request an exclusive copy (not because
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// of a pending invalidate). This can happen if the original
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// request was for a read-only (non-exclusive) block, but we
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// got an exclusive copy anyway because of the E part of the
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// MOESI/MESI protocol. Since we got the exclusive copy
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// there's no need to defer the targets, so move them up to
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// the regular target list.
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assert(!targets->needsExclusive);
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targets->needsExclusive = true;
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// if any of the deferred targets were upper-level cache
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// requests marked downstreamPending, need to clear that
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assert(!downstreamPending); // not pending here anymore
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deferredTargets->clearDownstreamPending();
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// this clears out deferredTargets too
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targets->splice(targets->end(), *deferredTargets);
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deferredTargets->resetFlags();
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}
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}
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bool
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MSHR::checkFunctional(PacketPtr pkt)
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{
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// For printing, we treat the MSHR as a whole as single entity.
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// For other requests, we iterate over the individual targets
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// since that's where the actual data lies.
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if (pkt->isPrint()) {
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pkt->checkFunctional(this, addr, size, NULL);
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return false;
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} else {
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return (targets->checkFunctional(pkt) ||
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deferredTargets->checkFunctional(pkt));
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}
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}
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void
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MSHR::print(std::ostream &os, int verbosity, const std::string &prefix) const
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{
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ccprintf(os, "%s[%x:%x] %s %s %s state: %s %s %s %s\n",
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prefix, addr, addr+size-1,
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isForward ? "Forward" : "",
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isForwardNoResponse() ? "ForwNoResp" : "",
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needsExclusive() ? "Excl" : "",
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_isUncacheable ? "Unc" : "",
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inService ? "InSvc" : "",
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downstreamPending ? "DwnPend" : "",
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hasPostInvalidate() ? "PostInv" : "",
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hasPostDowngrade() ? "PostDowngr" : "");
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ccprintf(os, "%s Targets:\n", prefix);
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targets->print(os, verbosity, prefix + " ");
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if (!deferredTargets->empty()) {
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ccprintf(os, "%s Deferred Targets:\n", prefix);
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deferredTargets->print(os, verbosity, prefix + " ");
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}
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}
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MSHR::~MSHR()
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{
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delete[] targets;
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delete[] deferredTargets;
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}
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