/**
* Add to sets coveredNodes and coveredArcs the cfg arcs that are now
* covered given the new region containing the translations in
* selectedVec.
*/
static void markCovered(const TransCFG& cfg, const RegionDescPtr region,
const TransIDVec& selectedVec, const TransIDSet heads,
TransIDSet& coveredNodes,
TransCFG::ArcPtrSet& coveredArcs) {
assert(selectedVec.size() > 0);
TransID newHead = selectedVec[0];
assert(!region->empty());
assert(newHead == getTransId(region->entry()->id()));
// Mark all region's nodes as covered.
coveredNodes.insert(selectedVec.begin(), selectedVec.end());
// Mark all incoming arcs into newHead from covered nodes as covered.
for (auto arc : cfg.inArcs(newHead)) {
TransID src = arc->src();
if (coveredNodes.count(src)) {
coveredArcs.insert(arc);
}
}
// Mark all CFG arcs within the region as covered.
region->forEachArc([&](RegionDesc::BlockId src, RegionDesc::BlockId dst) {
if (!hasTransId(src) || !hasTransId(dst)) return;
TransID srcTid = getTransId(src);
TransID dstTid = getTransId(dst);
assert(cfg.hasArc(srcTid, dstTid));
bool foundArc = false;
for (auto arc : cfg.outArcs(srcTid)) {
if (arc->dst() == dstTid) {
coveredArcs.insert(arc);
foundArc = true;
}
}
always_assert(foundArc);
});
// Mark all outgoing arcs from the region to a head node as covered.
for (auto node : selectedVec) {
for (auto arc : cfg.outArcs(node)) {
if (heads.count(arc->dst())) {
coveredArcs.insert(arc);
}
}
}
}
/**
* Add to sets coveredNodes and coveredArcs the cfg arcs that are now
* covered given the new region containing the translations in
* selectedVec.
*/
static void markCovered(const TransCFG& cfg, const TransIDVec selectedVec,
const TransIDSet heads, TransIDSet& coveredNodes,
TransCFG::ArcPtrSet& coveredArcs) {
assert(selectedVec.size() > 0);
TransID newHead = selectedVec[0];
// Mark all region's nodes as covered.
coveredNodes.insert(selectedVec.begin(), selectedVec.end());
// Mark all incoming arcs into newHead from covered nodes as covered.
for (auto arc : cfg.inArcs(newHead)) {
TransID src = arc->src();
if (coveredNodes.count(src)) {
coveredArcs.insert(arc);
}
}
// Mark all arcs between consecutive region nodes as covered.
for (size_t i = 0; i < selectedVec.size() - 1; i++) {
TransID node = selectedVec[i];
TransID next = selectedVec[i + 1];
bool foundArc = false;
for (auto arc : cfg.outArcs(node)) {
if (arc->dst() == next) {
coveredArcs.insert(arc);
foundArc = true;
}
}
always_assert(foundArc);
}
// Mark all outgoing arcs from the region to a head node as covered.
for (auto node : selectedVec) {
for (auto arc : cfg.outArcs(node)) {
if (heads.count(arc->dst())) {
coveredArcs.insert(arc);
}
}
}
}
/**
* Returns the sum of the weights of the arcs going from srcs to dst.
*/
static int64_t interRegionWeight(const TransIDVec& srcs,
TransID dst,
const TransCFG& cfg) {
int64_t totalWeight = 0;
for (auto src : srcs) {
for (auto arc : cfg.outArcs(src)) {
if (arc->dst() == dst) {
totalWeight += arc->weight();
}
}
}
return totalWeight;
}
/**
* Sorts the regions vector in a linear order to be used for
* translation. The goal is to obtain an order that improves locality
* when the function is executed. Each region is translated separately.
*/
static void sortRegions(RegionVec& regions,
const Func* func,
const TransCFG& cfg,
const ProfData* profData,
const TransIDToRegionMap& headToRegion,
const RegionToTransIDsMap& regionToTransIds) {
RegionVec sorted;
RegionSet selected;
if (regions.empty()) return;
// First, pick the region starting at the lowest bytecode offset.
// This will normally correspond to the main function entry (for
// normal, regular bytecode), but it may not be for irregular
// functions written in hhas (like array_map and array_filter). If
// there multiple regions starting at the lowest bytecode offset,
// pick the one with the largest profile weight.
RegionDescPtr entryRegion = nullptr;
int64_t maxEntryWeight = -1;
Offset lowestOffset = kInvalidOffset;
for (const auto& pair : regionToTransIds) {
auto r = pair.first;
auto& tids = pair.second;
TransID firstTid = tids[0];
Offset firstOffset = profData->transSrcKey(firstTid).offset();
int64_t weight = cfg.weight(firstTid);
if (lowestOffset == kInvalidOffset || firstOffset < lowestOffset ||
(firstOffset == lowestOffset && weight > maxEntryWeight)) {
entryRegion = r;
maxEntryWeight = weight;
lowestOffset = firstOffset;
}
}
assert(entryRegion);
sorted.push_back(entryRegion);
selected.insert(entryRegion);
RegionDescPtr region = entryRegion;
// Select the remaining regions, iteratively picking the most likely
// region to execute next.
for (auto i = 1; i < regions.size(); i++) {
int64_t maxWeight = -1;
int64_t maxHeadWeight = -1;
RegionDescPtr bestNext = nullptr;
auto regionTransIds = getRegionTransIDVec(regionToTransIds, region);
for (auto next : regions) {
if (selected.count(next)) continue;
auto nextTransIds = getRegionTransIDVec(regionToTransIds, next);
int64_t weight = interRegionWeight(regionTransIds, nextTransIds[0], cfg);
int64_t headWeight = cfg.weight(nextTransIds[0]);
if ((weight > maxWeight) ||
(weight == maxWeight && headWeight > maxHeadWeight)) {
maxWeight = weight;
maxHeadWeight = headWeight;
bestNext = next;
}
}
assert(bestNext);
sorted.push_back(bestNext);
selected.insert(bestNext);
region = bestNext;
}
assert(sorted.size() == regions.size());
regions = sorted;
if (debug && Trace::moduleEnabled(HPHP::Trace::pgo, 5)) {
for (size_t i = 0; i < regions.size(); i++) {
auto r = regions[i];
auto tids = getRegionTransIDVec(regionToTransIds, r);
std::string transIds = folly::join(", ", tids);
FTRACE(6, "sortRegions: region[{}]: {}\n", i, transIds);
}
}
}
RegionDescPtr selectHotTrace(TransID triggerId,
const ProfData* profData,
TransCFG& cfg,
TransIDSet& selectedSet,
TransIDVec* selectedVec) {
auto region = std::make_shared<RegionDesc>();
TransID tid = triggerId;
TransID prevId = kInvalidTransID;
selectedSet.clear();
if (selectedVec) selectedVec->clear();
PostConditions accumPostConds;
// Maps BlockIds to the set of BC offsets for its successor blocks.
// Used to prevent multiple successors with the same SrcKey for now.
// This can go away once task #4157613 is done.
hphp_hash_map<RegionDesc::BlockId, SrcKeySet> succSKSet;
// Maps from BlockIds to accumulated post conditions for that block.
// Used to determine if we can add branch-over edges by checking the
// pre-conditions of the successor block.
hphp_hash_map<RegionDesc::BlockId, PostConditions> blockPostConds;
while (!selectedSet.count(tid)) {
RegionDescPtr blockRegion = profData->transRegion(tid);
if (blockRegion == nullptr) break;
// If the debugger is attached, only allow single-block regions.
if (prevId != kInvalidTransID && isDebuggerAttachedProcess()) {
FTRACE(2, "selectHotTrace: breaking region at Translation {} "
"because of debugger is attached\n", tid);
break;
}
// Break if block is not the first and requires reffiness checks.
// Task #2589970: fix translateRegion to support mid-region reffiness checks
if (prevId != kInvalidTransID) {
auto nRefDeps = blockRegion->blocks[0]->reffinessPreds().size();
if (nRefDeps > 0) {
FTRACE(2, "selectHotTrace: breaking region because of refDeps ({}) at "
"Translation {}\n", nRefDeps, tid);
break;
}
}
// Break if block is not the first and it corresponds to the main
// function body entry. This is to prevent creating multiple
// large regions containing the function body (starting at various
// DV funclets).
if (prevId != kInvalidTransID) {
const Func* func = profData->transFunc(tid);
Offset bcOffset = profData->transStartBcOff(tid);
if (func->base() == bcOffset) {
FTRACE(2, "selectHotTrace: breaking region because reached the main "
"function body entry at Translation {} (BC offset {})\n",
tid, bcOffset);
break;
}
}
if (prevId != kInvalidTransID) {
auto sk = profData->transSrcKey(tid);
if (profData->optimized(sk)) {
FTRACE(2, "selectHotTrace: breaking region because next sk already "
"optimized, for Translation {}\n", tid);
break;
}
}
// Break trace if translation tid cannot follow the execution of
// the entire translation prevId. This can only happen if the
// execution of prevId takes a side exit that leads to the
// execution of tid.
if (prevId != kInvalidTransID) {
Op* lastInstr = profData->transLastInstr(prevId);
const Unit* unit = profData->transFunc(prevId)->unit();
OffsetSet succOffs = findSuccOffsets(lastInstr, unit);
if (!succOffs.count(profData->transSrcKey(tid).offset())) {
if (HPHP::Trace::moduleEnabled(HPHP::Trace::pgo, 2)) {
FTRACE(2, "selectHotTrace: WARNING: Breaking region @: {}\n",
show(*region));
FTRACE(2, "selectHotTrace: next translation selected: tid = {}\n{}\n",
tid, show(*blockRegion));
FTRACE(2, "\nsuccOffs = {}\n", folly::join(", ", succOffs));
}
break;
}
}
if (region->blocks.size() > 0) {
auto& newBlock = blockRegion->blocks.front();
auto newBlockId = newBlock->id();
auto predBlockId = region->blocks.back().get()->id();
if (!RuntimeOption::EvalHHIRBytecodeControlFlow) {
region->addArc(predBlockId, newBlockId);
} else {
// With bytecode control-flow, we add all forward arcs in the TransCFG
// that are induced by the blocks in the region, as a simple way
// to expose control-flow for now.
// This can go away once Task #4075822 is done.
auto newBlockSrcKey = blockRegion->blocks.front().get()->start();
if (succSKSet[predBlockId].count(newBlockSrcKey)) break;
region->addArc(predBlockId, newBlockId);
succSKSet[predBlockId].insert(newBlockSrcKey);
assert(hasTransId(newBlockId));
auto newTransId = getTransId(newBlockId);
for (auto iOther = 0; iOther < region->blocks.size(); iOther++) {
auto other = region->blocks[iOther];
auto otherBlockId = other.get()->id();
if (!hasTransId(otherBlockId)) continue;
auto otherTransId = getTransId(otherBlockId);
auto otherBlockSrcKey = other.get()->start();
if (cfg.hasArc(otherTransId, newTransId) &&
!other.get()->inlinedCallee() &&
// Task #4157613 will allow the following check to go away
!succSKSet[otherBlockId].count(newBlockSrcKey) &&
preCondsAreSatisfied(newBlock, blockPostConds[otherBlockId])) {
region->addArc(otherBlockId, newBlockId);
succSKSet[otherBlockId].insert(newBlockSrcKey);
}
// When Eval.JitLoops is set, insert back-edges in the
// region if they exist in the TransCFG.
if (RuntimeOption::EvalJitLoops &&
cfg.hasArc(newTransId, otherTransId) &&
// Task #4157613 will allow the following check to go away
!succSKSet[newBlockId].count(otherBlockSrcKey)) {
region->addArc(newBlockId, otherBlockId);
succSKSet[newBlockId].insert(otherBlockSrcKey);
}
}
}
}
region->blocks.insert(region->blocks.end(), blockRegion->blocks.begin(),
blockRegion->blocks.end());
region->arcs.insert(region->arcs.end(), blockRegion->arcs.begin(),
blockRegion->arcs.end());
if (cfg.outArcs(tid).size() > 1) {
region->setSideExitingBlock(blockRegion->blocks.front()->id());
}
selectedSet.insert(tid);
if (selectedVec) selectedVec->push_back(tid);
Op lastOp = *(profData->transLastInstr(tid));
if (breaksRegion(lastOp)) {
FTRACE(2, "selectHotTrace: breaking region because of last instruction "
"in Translation {}: {}\n", tid, opcodeToName(lastOp));
break;
}
auto outArcs = cfg.outArcs(tid);
if (outArcs.size() == 0) {
FTRACE(2, "selectHotTrace: breaking region because there's no successor "
"for Translation {}\n", tid);
break;
}
auto lastNewBlock = blockRegion->blocks.back();
discardPoppedTypes(accumPostConds,
blockRegion->blocks[0]->initialSpOffset());
mergePostConds(accumPostConds, lastNewBlock->postConds());
blockPostConds[lastNewBlock->id()] = accumPostConds;
TransCFG::ArcPtrVec possibleOutArcs;
for (auto arc : outArcs) {
RegionDesc::BlockPtr possibleNext =
profData->transRegion(arc->dst())->blocks[0];
if (preCondsAreSatisfied(possibleNext, accumPostConds)) {
possibleOutArcs.emplace_back(arc);
}
}
if (possibleOutArcs.size() == 0) {
FTRACE(2, "selectHotTrace: breaking region because postcondition check "
"pruned all successors of Translation {}\n", tid);
break;
}
auto maxWeight = std::numeric_limits<int64_t>::min();
TransCFG::Arc* maxArc = nullptr;
for (auto arc : possibleOutArcs) {
if (arc->weight() >= maxWeight) {
maxWeight = arc->weight();
maxArc = arc;
}
}
assert(maxArc != nullptr);
prevId = tid;
tid = maxArc->dst();
}
return region;
}
RegionDescPtr selectHotTrace(TransID triggerId,
const ProfData* profData,
TransCFG& cfg,
TransIDSet& selectedSet,
TransIDVec* selectedVec) {
auto region = std::make_shared<RegionDesc>();
TransID tid = triggerId;
TransID prevId = kInvalidTransID;
selectedSet.clear();
if (selectedVec) selectedVec->clear();
PostConditions accumPostConds;
// Maps from BlockIds to accumulated post conditions for that block.
// Used to determine if we can add branch-over edges by checking the
// pre-conditions of the successor block.
hphp_hash_map<RegionDesc::BlockId, PostConditions> blockPostConds;
uint32_t numBCInstrs = 0;
while (!selectedSet.count(tid)) {
RegionDescPtr blockRegion = profData->transRegion(tid);
if (blockRegion == nullptr) break;
// Break if region would be larger than the specified limit.
auto newInstrSize = numBCInstrs + blockRegion->instrSize();
if (newInstrSize > RuntimeOption::EvalJitMaxRegionInstrs) {
FTRACE(2, "selectHotTrace: breaking region at Translation {} because "
"size ({}) would exceed of maximum translation limit\n",
tid, newInstrSize);
break;
}
// If the debugger is attached, only allow single-block regions.
if (prevId != kInvalidTransID && isDebuggerAttachedProcess()) {
FTRACE(2, "selectHotTrace: breaking region at Translation {} "
"because of debugger is attached\n", tid);
break;
}
// Break if block is not the first and it corresponds to the main
// function body entry. This is to prevent creating multiple
// large regions containing the function body (starting at various
// DV funclets).
if (prevId != kInvalidTransID) {
const Func* func = profData->transFunc(tid);
Offset bcOffset = profData->transStartBcOff(tid);
if (func->base() == bcOffset) {
FTRACE(2, "selectHotTrace: breaking region because reached the main "
"function body entry at Translation {} (BC offset {})\n",
tid, bcOffset);
break;
}
}
if (prevId != kInvalidTransID) {
auto sk = profData->transSrcKey(tid);
if (profData->optimized(sk)) {
FTRACE(2, "selectHotTrace: breaking region because next sk already "
"optimized, for Translation {}\n", tid);
break;
}
}
bool hasPredBlock = !region->empty();
RegionDesc::BlockId predBlockId = (hasPredBlock ?
region->blocks().back().get()->id() : 0);
auto const& newFirstBlock = blockRegion->entry();
auto newFirstBlockId = newFirstBlock->id();
auto newLastBlockId = blockRegion->blocks().back()->id();
// Add blockRegion's blocks and arcs to region.
region->append(*blockRegion);
numBCInstrs += blockRegion->instrSize();
if (hasPredBlock) {
region->addArc(predBlockId, newFirstBlockId);
}
// When Eval.JitLoops is set, insert back-edges in the region if
// they exist in the TransCFG.
if (RuntimeOption::EvalJitLoops) {
assertx(hasTransId(newFirstBlockId));
auto newTransId = getTransId(newFirstBlockId);
// Don't add the arc if the last opcode in the source block ends
// the region.
if (!breaksRegion(*profData->transLastInstr(newTransId))) {
auto& blocks = region->blocks();
for (auto iOther = 0; iOther < blocks.size(); iOther++) {
auto other = blocks[iOther];
auto otherFirstBlockId = other.get()->id();
if (!hasTransId(otherFirstBlockId)) continue;
auto otherTransId = getTransId(otherFirstBlockId);
if (cfg.hasArc(newTransId, otherTransId)) {
region->addArc(newLastBlockId, otherFirstBlockId);
}
}
}
}
if (cfg.outArcs(tid).size() > 1) {
region->setSideExitingBlock(blockRegion->entry()->id());
}
selectedSet.insert(tid);
if (selectedVec) selectedVec->push_back(tid);
Op lastOp = *(profData->transLastInstr(tid));
if (breaksRegion(lastOp)) {
FTRACE(2, "selectHotTrace: breaking region because of last instruction "
"in Translation {}: {}\n", tid, opcodeToName(lastOp));
break;
}
auto outArcs = cfg.outArcs(tid);
if (outArcs.size() == 0) {
FTRACE(2, "selectHotTrace: breaking region because there's no successor "
"for Translation {}\n", tid);
break;
}
auto newLastBlock = blockRegion->blocks().back();
discardPoppedTypes(accumPostConds,
blockRegion->entry()->initialSpOffset());
mergePostConds(accumPostConds, newLastBlock->postConds());
blockPostConds[newLastBlock->id()] = accumPostConds;
TransCFG::ArcPtrVec possibleOutArcs;
for (auto arc : outArcs) {
RegionDesc::BlockPtr possibleNext =
profData->transRegion(arc->dst())->entry();
if (preCondsAreSatisfied(possibleNext, accumPostConds)) {
possibleOutArcs.emplace_back(arc);
}
}
if (possibleOutArcs.size() == 0) {
FTRACE(2, "selectHotTrace: breaking region because postcondition check "
"pruned all successors of Translation {}\n", tid);
break;
}
auto maxWeight = std::numeric_limits<int64_t>::min();
TransCFG::Arc* maxArc = nullptr;
for (auto arc : possibleOutArcs) {
if (arc->weight() >= maxWeight) {
maxWeight = arc->weight();
maxArc = arc;
}
}
assertx(maxArc != nullptr);
prevId = tid;
tid = maxArc->dst();
}
FTRACE(3, "selectHotTrace: before chainRetransBlocks:\n{}\n", show(*region));
region->chainRetransBlocks();
FTRACE(3, "selectHotTrace: after chainRetransBlocks:\n{}\n", show(*region));
return region;
}
/**
* Sorts the regions vector in a linear order to be used for
* translation. The goal is to obtain an order that improves locality
* when the function is executed.
*/
static void sortRegion(RegionVec& regions,
const Func* func,
const TransCFG& cfg,
const ProfData* profData,
const TransIDToRegionMap& headToRegion,
const RegionToTransIDsMap& regionToTransIds) {
RegionVec sorted;
RegionSet selected;
// First, pick the region for the function body entry. There may be
// multiple translations of the function body, so pick the one with
// largest profile weight.
RegionDescPtr entryRegion = nullptr;
int64_t maxEntryWeight = -1;
for (const auto& pair : regionToTransIds) {
auto r = pair.first;
auto& tids = pair.second;
for (auto tid : tids) {
if (profData->transSrcKey(tid).offset() == func->base()) {
int64_t weight = cfg.weight(tid);
if (weight > maxEntryWeight) {
entryRegion = r;
maxEntryWeight = weight;
}
}
}
}
assert(entryRegion);
sorted.push_back(entryRegion);
selected.insert(entryRegion);
RegionDescPtr region = entryRegion;
// Select the remaining regions, iteratively picking the most likely
// region to execute next.
for (auto i = 1; i < regions.size(); i++) {
int64_t maxWeight = -1;
int64_t maxHeadWeight = -1;
RegionDescPtr bestNext = nullptr;
auto regionTransIds = getRegionTransIDVec(regionToTransIds, region);
for (auto next : regions) {
if (setContains(selected, next)) continue;
auto nextTransIds = getRegionTransIDVec(regionToTransIds, next);
int64_t weight = interRegionWeight(regionTransIds, nextTransIds[0], cfg);
int64_t headWeight = cfg.weight(nextTransIds[0]);
if ((weight > maxWeight) ||
(weight == maxWeight && headWeight > maxHeadWeight)) {
maxWeight = weight;
maxHeadWeight = headWeight;
bestNext = next;
}
}
assert(bestNext);
sorted.push_back(bestNext);
selected.insert(bestNext);
region = bestNext;
}
assert(sorted.size() == regions.size());
regions = sorted;
if (debug && Trace::moduleEnabled(HPHP::Trace::pgo, 5)) {
for (size_t i = 0; i < regions.size(); i++) {
auto r = regions[i];
auto tids = getRegionTransIDVec(regionToTransIds, r);
std::string transIds = folly::join(", ", tids);
FTRACE(6, "sortRegion: region[{}]: {}\n", i, transIds);
}
}
}
RegionDescPtr selectHotTrace(TransID triggerId,
const ProfData* profData,
TransCFG& cfg,
TransIDSet& selectedSet,
TransIDVec* selectedVec) {
auto region = std::make_shared<RegionDesc>();
TransID tid = triggerId;
TransID prevId = InvalidID;
selectedSet.clear();
if (selectedVec) selectedVec->clear();
PostConditions accumPostConds;
while (!selectedSet.count(tid)) {
RegionDescPtr blockRegion = profData->transRegion(tid);
if (blockRegion == nullptr) break;
// If the debugger is attached, only allow single-block regions.
if (prevId != InvalidID && isDebuggerAttachedProcess()) {
FTRACE(2, "selectHotTrace: breaking region at Translation {} "
"because of debugger is attached\n", tid);
break;
}
// Break if block is not the first and requires reffiness checks.
// Task #2589970: fix translateRegion to support mid-region reffiness checks
if (prevId != InvalidID) {
auto nRefDeps = blockRegion->blocks[0]->reffinessPreds().size();
if (nRefDeps > 0) {
FTRACE(2, "selectHotTrace: breaking region because of refDeps ({}) at "
"Translation {}\n", nRefDeps, tid);
break;
}
}
// Break if block is not the first and it corresponds to the main
// function body entry. This is to prevent creating multiple
// large regions containing the function body (starting at various
// DV funclets).
if (prevId != InvalidID) {
const Func* func = profData->transFunc(tid);
Offset bcOffset = profData->transStartBcOff(tid);
if (func->base() == bcOffset) {
FTRACE(2, "selectHotTrace: breaking region because reached the main "
"function body entry at Translation {} (BC offset {})\n",
tid, bcOffset);
break;
}
}
if (prevId != InvalidID) {
auto sk = profData->transSrcKey(tid);
if (profData->optimized(sk)) {
FTRACE(2, "selectHotTrace: breaking region because next sk already "
"optimized, for Translation {}\n", tid);
break;
}
}
// Break trace if translation tid cannot follow the execution of
// the entire translation prevId. This can only happen if the
// execution of prevId takes a side exit that leads to the
// execution of tid.
if (prevId != InvalidID) {
Op* lastInstr = profData->transLastInstr(prevId);
const Unit* unit = profData->transFunc(prevId)->unit();
OffsetSet succOffs = findSuccOffsets(lastInstr, unit);
if (!succOffs.count(profData->transSrcKey(tid).offset())) {
if (HPHP::Trace::moduleEnabled(HPHP::Trace::pgo, 2)) {
FTRACE(2, "selectHotTrace: WARNING: Breaking region @: {}\n",
JIT::show(*region));
FTRACE(2, "selectHotTrace: next translation selected: tid = {}\n{}\n",
tid, JIT::show(*blockRegion));
FTRACE(2, "\nsuccOffs = {}\n", folly::join(", ", succOffs));
}
break;
}
}
region->blocks.insert(region->blocks.end(), blockRegion->blocks.begin(),
blockRegion->blocks.end());
selectedSet.insert(tid);
if (selectedVec) selectedVec->push_back(tid);
Op lastOp = *(profData->transLastInstr(tid));
if (breaksRegion(lastOp)) {
FTRACE(2, "selectHotTrace: breaking region because of last instruction "
"in Translation {}: {}\n", tid, opcodeToName(lastOp));
break;
}
auto outArcs = cfg.outArcs(tid);
if (outArcs.size() == 0) {
FTRACE(2, "selectHotTrace: breaking region because there's no successor "
"for Translation {}\n", tid);
break;
}
auto lastNewBlock = blockRegion->blocks.back();
discardPoppedTypes(accumPostConds,
blockRegion->blocks[0]->initialSpOffset());
mergePostConds(accumPostConds, lastNewBlock->postConds());
TransCFG::ArcPtrVec possibleOutArcs;
for (auto arc : outArcs) {
RegionDesc::BlockPtr possibleNext =
profData->transRegion(arc->dst())->blocks[0];
if (preCondsAreSatisfied(possibleNext, accumPostConds)) {
possibleOutArcs.emplace_back(arc);
}
}
if (possibleOutArcs.size() == 0) {
FTRACE(2, "selectHotTrace: breaking region because postcondition check "
"pruned all successors of Translation {}\n", tid);
break;
}
auto maxWeight = std::numeric_limits<int64_t>::min();
TransCFG::Arc* maxArc = nullptr;
for (auto arc : possibleOutArcs) {
if (arc->weight() >= maxWeight) {
maxWeight = arc->weight();
maxArc = arc;
}
}
assert(maxArc != nullptr);
prevId = tid;
tid = maxArc->dst();
}
return region;
}
RegionDescPtr selectHotTrace(TransID triggerId,
const ProfData* profData,
TransCFG& cfg,
TransIDSet& selectedSet,
TransIDVec* selectedVec) {
auto region = std::make_shared<RegionDesc>();
TransID tid = triggerId;
TransID prevId = kInvalidTransID;
selectedSet.clear();
if (selectedVec) selectedVec->clear();
PostConditions accumPostConds;
// Maps BlockIds to the set of BC offsets for its successor blocks.
// Used to prevent multiple successors with the same SrcKey for now.
// This can go away once task #4157613 is done.
hphp_hash_map<RegionDesc::BlockId, SrcKeySet> succSKSet;
// Maps from BlockIds to accumulated post conditions for that block.
// Used to determine if we can add branch-over edges by checking the
// pre-conditions of the successor block.
hphp_hash_map<RegionDesc::BlockId, PostConditions> blockPostConds;
while (!selectedSet.count(tid)) {
RegionDescPtr blockRegion = profData->transRegion(tid);
if (blockRegion == nullptr) break;
// If the debugger is attached, only allow single-block regions.
if (prevId != kInvalidTransID && isDebuggerAttachedProcess()) {
FTRACE(2, "selectHotTrace: breaking region at Translation {} "
"because of debugger is attached\n", tid);
break;
}
// Break if block is not the first and it corresponds to the main
// function body entry. This is to prevent creating multiple
// large regions containing the function body (starting at various
// DV funclets).
if (prevId != kInvalidTransID) {
const Func* func = profData->transFunc(tid);
Offset bcOffset = profData->transStartBcOff(tid);
if (func->base() == bcOffset) {
FTRACE(2, "selectHotTrace: breaking region because reached the main "
"function body entry at Translation {} (BC offset {})\n",
tid, bcOffset);
break;
}
}
if (prevId != kInvalidTransID) {
auto sk = profData->transSrcKey(tid);
if (profData->optimized(sk)) {
FTRACE(2, "selectHotTrace: breaking region because next sk already "
"optimized, for Translation {}\n", tid);
break;
}
}
bool hasPredBlock = !region->empty();
RegionDesc::BlockId predBlockId = (hasPredBlock ?
region->blocks().back().get()->id() : 0);
auto const& newFirstBlock = blockRegion->entry();
auto newFirstBlockId = newFirstBlock->id();
auto newFirstBlockSk = newFirstBlock->start();
auto newLastBlockId = blockRegion->blocks().back()->id();
// Make sure we don't end up with multiple successors for the same
// SrcKey. Task #4157613 will allow the following check to go away.
// This needs to be done before we insert blockRegion into region,
// to avoid creating unreachable blocks.
if (RuntimeOption::EvalHHIRBytecodeControlFlow && hasPredBlock &&
succSKSet[predBlockId].count(newFirstBlockSk)) {
break;
}
// Add blockRegion's blocks and arcs to region.
region->append(*blockRegion);
if (hasPredBlock) {
if (RuntimeOption::EvalHHIRBytecodeControlFlow) {
// This is checked above.
assert(succSKSet[predBlockId].count(newFirstBlockSk) == 0);
succSKSet[predBlockId].insert(newFirstBlockSk);
}
region->addArc(predBlockId, newFirstBlockId);
}
// With bytecode control-flow, we add all forward arcs in the TransCFG
// that are induced by the blocks in the region, as a simple way
// to expose control-flow for now.
// This can go away once Task #4075822 is done.
if (RuntimeOption::EvalHHIRBytecodeControlFlow) {
assert(hasTransId(newFirstBlockId));
auto newTransId = getTransId(newFirstBlockId);
auto& blocks = region->blocks();
for (auto iOther = 0; iOther < blocks.size(); iOther++) {
auto other = blocks[iOther];
auto otherFirstBlockId = other.get()->id();
if (!hasTransId(otherFirstBlockId)) continue;
auto otherTransId = getTransId(otherFirstBlockId);
auto otherFirstBlockSk = other.get()->start();
auto otherRegion = profData->transRegion(otherTransId);
auto otherLastBlockId = otherRegion->blocks().back()->id();
// When loops are off, stop once we hit the newTransId we just inserted.
if (!RuntimeOption::EvalJitLoops && otherTransId == newTransId) break;
if (cfg.hasArc(otherTransId, newTransId) &&
// Task #4157613 will allow the following check to go away
!succSKSet[otherLastBlockId].count(newFirstBlockSk) &&
preCondsAreSatisfied(newFirstBlock,
blockPostConds[otherLastBlockId])) {
region->addArc(otherLastBlockId, newFirstBlockId);
succSKSet[otherLastBlockId].insert(newFirstBlockSk);
}
// When Eval.JitLoops is set, insert back-edges in the
// region if they exist in the TransCFG.
if (RuntimeOption::EvalJitLoops &&
cfg.hasArc(newTransId, otherTransId) &&
// Task #4157613 will allow the following check to go away
!succSKSet[newLastBlockId].count(otherFirstBlockSk)) {
region->addArc(newLastBlockId, otherFirstBlockId);
succSKSet[newLastBlockId].insert(otherFirstBlockSk);
}
}
}
if (cfg.outArcs(tid).size() > 1) {
region->setSideExitingBlock(blockRegion->entry()->id());
}
selectedSet.insert(tid);
if (selectedVec) selectedVec->push_back(tid);
Op lastOp = *(profData->transLastInstr(tid));
if (breaksRegion(lastOp)) {
FTRACE(2, "selectHotTrace: breaking region because of last instruction "
"in Translation {}: {}\n", tid, opcodeToName(lastOp));
break;
}
auto outArcs = cfg.outArcs(tid);
if (outArcs.size() == 0) {
FTRACE(2, "selectHotTrace: breaking region because there's no successor "
"for Translation {}\n", tid);
break;
}
auto newLastBlock = blockRegion->blocks().back();
discardPoppedTypes(accumPostConds,
blockRegion->entry()->initialSpOffset());
mergePostConds(accumPostConds, newLastBlock->postConds());
blockPostConds[newLastBlock->id()] = accumPostConds;
TransCFG::ArcPtrVec possibleOutArcs;
for (auto arc : outArcs) {
RegionDesc::BlockPtr possibleNext =
profData->transRegion(arc->dst())->entry();
if (preCondsAreSatisfied(possibleNext, accumPostConds)) {
possibleOutArcs.emplace_back(arc);
}
}
if (possibleOutArcs.size() == 0) {
FTRACE(2, "selectHotTrace: breaking region because postcondition check "
"pruned all successors of Translation {}\n", tid);
break;
}
auto maxWeight = std::numeric_limits<int64_t>::min();
TransCFG::Arc* maxArc = nullptr;
for (auto arc : possibleOutArcs) {
if (arc->weight() >= maxWeight) {
maxWeight = arc->weight();
maxArc = arc;
}
}
assert(maxArc != nullptr);
prevId = tid;
tid = maxArc->dst();
}
return region;
}
RegionDescPtr selectHotTrace(TransID triggerId,
const ProfData* profData,
TransCFG& cfg,
TransIDSet& selectedSet) {
JIT::RegionDescPtr region = smart::make_unique<JIT::RegionDesc>();
TransID tid = triggerId;
TransID prevId = InvalidID;
selectedSet.clear();
while (!setContains(selectedSet, tid)) {
RegionDesc::BlockPtr block = profData->transBlock(tid);
if (block == nullptr) break;
// If the debugger is attached, only allow single-block regions.
if (prevId != InvalidID && isDebuggerAttachedProcess()) {
FTRACE(5, "selectHotRegion: breaking region at Translation {} "
"because of debugger is attached\n", tid);
break;
}
// Break if block is not the first and requires reffiness checks.
// Task #2589970: fix translateRegion to support mid-region reffiness checks
if (prevId != InvalidID) {
auto nRefDeps = block->reffinessPreds().size();
if (nRefDeps > 0) {
FTRACE(5, "selectHotRegion: breaking region because of refDeps ({}) at "
"Translation {}\n", nRefDeps, tid);
break;
}
}
// Break trace if translation tid cannot follow the execution of
// the entire translation prevTd. This can only happen if the
// execution of prevId takes a side exit that leads to the
// execution of tid.
if (prevId != InvalidID) {
Op* lastInstr = profData->transLastInstr(prevId);
const Unit* unit = profData->transFunc(prevId)->unit();
OffsetSet succOffs = findSuccOffsets(lastInstr, unit);
if (!setContains(succOffs, profData->transSrcKey(tid).offset())) {
if (HPHP::Trace::moduleEnabled(HPHP::Trace::pgo, 5)) {
FTRACE(5, "selectHotTrace: WARNING: Breaking region @: {}\n",
JIT::show(*region));
FTRACE(5, "selectHotTrace: next translation selected: tid = {}\n{}\n",
tid, JIT::show(*block));
std::string succStr("succOffs = ");
for (auto succ : succOffs) {
succStr += lexical_cast<std::string>(succ);
}
FTRACE(5, "\n{}\n", succStr);
}
break;
}
}
region->blocks.emplace_back(block);
selectedSet.insert(tid);
Op lastOp = *(profData->transLastInstr(tid));
if (breaksRegion(lastOp)) {
FTRACE(5, "selectHotTrace: breaking region because of last instruction "
"in Translation {}: {}\n", tid, opcodeToName(lastOp));
break;
}
auto outArcs = cfg.outArcs(tid);
if (outArcs.size() == 0) {
FTRACE(5, "selectHotTrace: breaking region because there's no successor "
"for Translation {}\n", tid);
break;
}
auto maxWeight = std::numeric_limits<int64_t>::min();
TransCFG::Arc* maxArc = nullptr;
for (auto arc : outArcs) {
if (arc->weight() >= maxWeight) {
maxWeight = arc->weight();
maxArc = arc;
}
}
assert(maxArc != nullptr);
prevId = tid;
tid = maxArc->dst();
}
return region;
}
