mirror of
https://github.com/RPCS3/llvm-mirror.git
synced 2024-11-22 10:42:39 +01:00
f58ab2a818
log:
BB [7, 8): begin {}, end {}, livein {}, liveout {}
BB [1, 2): begin {}, end {}, livein {}, liveout {}
...
But it is not convenient to know what the basic block is.
So I add the basic block name to it.
Reviewed By: vitalybuka
TestPlan: check-llvm
Differential Revision: https://reviews.llvm.org/D87152
403 lines
13 KiB
C++
403 lines
13 KiB
C++
//===- StackLifetime.cpp - Alloca Lifetime 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
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "llvm/Analysis/StackLifetime.h"
|
|
#include "llvm/ADT/DepthFirstIterator.h"
|
|
#include "llvm/ADT/STLExtras.h"
|
|
#include "llvm/ADT/SmallVector.h"
|
|
#include "llvm/ADT/StringExtras.h"
|
|
#include "llvm/Analysis/ValueTracking.h"
|
|
#include "llvm/Config/llvm-config.h"
|
|
#include "llvm/IR/AssemblyAnnotationWriter.h"
|
|
#include "llvm/IR/BasicBlock.h"
|
|
#include "llvm/IR/CFG.h"
|
|
#include "llvm/IR/InstIterator.h"
|
|
#include "llvm/IR/Instructions.h"
|
|
#include "llvm/IR/IntrinsicInst.h"
|
|
#include "llvm/IR/Intrinsics.h"
|
|
#include "llvm/IR/User.h"
|
|
#include "llvm/IR/Value.h"
|
|
#include "llvm/Pass.h"
|
|
#include "llvm/Support/Casting.h"
|
|
#include "llvm/Support/CommandLine.h"
|
|
#include "llvm/Support/Compiler.h"
|
|
#include "llvm/Support/Debug.h"
|
|
#include "llvm/Support/FormattedStream.h"
|
|
#include <algorithm>
|
|
#include <memory>
|
|
#include <tuple>
|
|
|
|
using namespace llvm;
|
|
|
|
#define DEBUG_TYPE "stack-lifetime"
|
|
|
|
const StackLifetime::LiveRange &
|
|
StackLifetime::getLiveRange(const AllocaInst *AI) const {
|
|
const auto IT = AllocaNumbering.find(AI);
|
|
assert(IT != AllocaNumbering.end());
|
|
return LiveRanges[IT->second];
|
|
}
|
|
|
|
bool StackLifetime::isReachable(const Instruction *I) const {
|
|
return BlockInstRange.find(I->getParent()) != BlockInstRange.end();
|
|
}
|
|
|
|
bool StackLifetime::isAliveAfter(const AllocaInst *AI,
|
|
const Instruction *I) const {
|
|
const BasicBlock *BB = I->getParent();
|
|
auto ItBB = BlockInstRange.find(BB);
|
|
assert(ItBB != BlockInstRange.end() && "Unreachable is not expected");
|
|
|
|
// Search the block for the first instruction following 'I'.
|
|
auto It = std::upper_bound(Instructions.begin() + ItBB->getSecond().first + 1,
|
|
Instructions.begin() + ItBB->getSecond().second, I,
|
|
[](const Instruction *L, const Instruction *R) {
|
|
return L->comesBefore(R);
|
|
});
|
|
--It;
|
|
unsigned InstNum = It - Instructions.begin();
|
|
return getLiveRange(AI).test(InstNum);
|
|
}
|
|
|
|
// Returns unique alloca annotated by lifetime marker only if
|
|
// markers has the same size and points to the alloca start.
|
|
static const AllocaInst *findMatchingAlloca(const IntrinsicInst &II,
|
|
const DataLayout &DL) {
|
|
const AllocaInst *AI = findAllocaForValue(II.getArgOperand(1), true);
|
|
if (!AI)
|
|
return nullptr;
|
|
|
|
auto AllocaSizeInBits = AI->getAllocationSizeInBits(DL);
|
|
if (!AllocaSizeInBits)
|
|
return nullptr;
|
|
int64_t AllocaSize = AllocaSizeInBits.getValue() / 8;
|
|
|
|
auto *Size = dyn_cast<ConstantInt>(II.getArgOperand(0));
|
|
if (!Size)
|
|
return nullptr;
|
|
int64_t LifetimeSize = Size->getSExtValue();
|
|
|
|
if (LifetimeSize != -1 && LifetimeSize != AllocaSize)
|
|
return nullptr;
|
|
|
|
return AI;
|
|
}
|
|
|
|
void StackLifetime::collectMarkers() {
|
|
InterestingAllocas.resize(NumAllocas);
|
|
DenseMap<const BasicBlock *, SmallDenseMap<const IntrinsicInst *, Marker>>
|
|
BBMarkerSet;
|
|
|
|
const DataLayout &DL = F.getParent()->getDataLayout();
|
|
|
|
// Compute the set of start/end markers per basic block.
|
|
for (const BasicBlock *BB : depth_first(&F)) {
|
|
for (const Instruction &I : *BB) {
|
|
const IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I);
|
|
if (!II || !II->isLifetimeStartOrEnd())
|
|
continue;
|
|
const AllocaInst *AI = findMatchingAlloca(*II, DL);
|
|
if (!AI) {
|
|
HasUnknownLifetimeStartOrEnd = true;
|
|
continue;
|
|
}
|
|
auto It = AllocaNumbering.find(AI);
|
|
if (It == AllocaNumbering.end())
|
|
continue;
|
|
auto AllocaNo = It->second;
|
|
bool IsStart = II->getIntrinsicID() == Intrinsic::lifetime_start;
|
|
if (IsStart)
|
|
InterestingAllocas.set(AllocaNo);
|
|
BBMarkerSet[BB][II] = {AllocaNo, IsStart};
|
|
}
|
|
}
|
|
|
|
// Compute instruction numbering. Only the following instructions are
|
|
// considered:
|
|
// * Basic block entries
|
|
// * Lifetime markers
|
|
// For each basic block, compute
|
|
// * the list of markers in the instruction order
|
|
// * the sets of allocas whose lifetime starts or ends in this BB
|
|
LLVM_DEBUG(dbgs() << "Instructions:\n");
|
|
for (const BasicBlock *BB : depth_first(&F)) {
|
|
LLVM_DEBUG(dbgs() << " " << Instructions.size() << ": BB " << BB->getName()
|
|
<< "\n");
|
|
auto BBStart = Instructions.size();
|
|
Instructions.push_back(nullptr);
|
|
|
|
BlockLifetimeInfo &BlockInfo =
|
|
BlockLiveness.try_emplace(BB, NumAllocas).first->getSecond();
|
|
|
|
auto &BlockMarkerSet = BBMarkerSet[BB];
|
|
if (BlockMarkerSet.empty()) {
|
|
BlockInstRange[BB] = std::make_pair(BBStart, Instructions.size());
|
|
continue;
|
|
}
|
|
|
|
auto ProcessMarker = [&](const IntrinsicInst *I, const Marker &M) {
|
|
LLVM_DEBUG(dbgs() << " " << Instructions.size() << ": "
|
|
<< (M.IsStart ? "start " : "end ") << M.AllocaNo
|
|
<< ", " << *I << "\n");
|
|
|
|
BBMarkers[BB].push_back({Instructions.size(), M});
|
|
Instructions.push_back(I);
|
|
|
|
if (M.IsStart) {
|
|
BlockInfo.End.reset(M.AllocaNo);
|
|
BlockInfo.Begin.set(M.AllocaNo);
|
|
} else {
|
|
BlockInfo.Begin.reset(M.AllocaNo);
|
|
BlockInfo.End.set(M.AllocaNo);
|
|
}
|
|
};
|
|
|
|
if (BlockMarkerSet.size() == 1) {
|
|
ProcessMarker(BlockMarkerSet.begin()->getFirst(),
|
|
BlockMarkerSet.begin()->getSecond());
|
|
} else {
|
|
// Scan the BB to determine the marker order.
|
|
for (const Instruction &I : *BB) {
|
|
const IntrinsicInst *II = dyn_cast<IntrinsicInst>(&I);
|
|
if (!II)
|
|
continue;
|
|
auto It = BlockMarkerSet.find(II);
|
|
if (It == BlockMarkerSet.end())
|
|
continue;
|
|
ProcessMarker(II, It->getSecond());
|
|
}
|
|
}
|
|
|
|
BlockInstRange[BB] = std::make_pair(BBStart, Instructions.size());
|
|
}
|
|
}
|
|
|
|
void StackLifetime::calculateLocalLiveness() {
|
|
bool Changed = true;
|
|
while (Changed) {
|
|
Changed = false;
|
|
|
|
for (const BasicBlock *BB : depth_first(&F)) {
|
|
BlockLifetimeInfo &BlockInfo = BlockLiveness.find(BB)->getSecond();
|
|
|
|
// Compute LiveIn by unioning together the LiveOut sets of all preds.
|
|
BitVector LocalLiveIn;
|
|
for (auto *PredBB : predecessors(BB)) {
|
|
LivenessMap::const_iterator I = BlockLiveness.find(PredBB);
|
|
// If a predecessor is unreachable, ignore it.
|
|
if (I == BlockLiveness.end())
|
|
continue;
|
|
switch (Type) {
|
|
case LivenessType::May:
|
|
LocalLiveIn |= I->second.LiveOut;
|
|
break;
|
|
case LivenessType::Must:
|
|
if (LocalLiveIn.empty())
|
|
LocalLiveIn = I->second.LiveOut;
|
|
else
|
|
LocalLiveIn &= I->second.LiveOut;
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Compute LiveOut by subtracting out lifetimes that end in this
|
|
// block, then adding in lifetimes that begin in this block. If
|
|
// we have both BEGIN and END markers in the same basic block
|
|
// then we know that the BEGIN marker comes after the END,
|
|
// because we already handle the case where the BEGIN comes
|
|
// before the END when collecting the markers (and building the
|
|
// BEGIN/END vectors).
|
|
BitVector LocalLiveOut = LocalLiveIn;
|
|
LocalLiveOut.reset(BlockInfo.End);
|
|
LocalLiveOut |= BlockInfo.Begin;
|
|
|
|
// Update block LiveIn set, noting whether it has changed.
|
|
if (LocalLiveIn.test(BlockInfo.LiveIn)) {
|
|
BlockInfo.LiveIn |= LocalLiveIn;
|
|
}
|
|
|
|
// Update block LiveOut set, noting whether it has changed.
|
|
if (LocalLiveOut.test(BlockInfo.LiveOut)) {
|
|
Changed = true;
|
|
BlockInfo.LiveOut |= LocalLiveOut;
|
|
}
|
|
}
|
|
} // while changed.
|
|
}
|
|
|
|
void StackLifetime::calculateLiveIntervals() {
|
|
for (auto IT : BlockLiveness) {
|
|
const BasicBlock *BB = IT.getFirst();
|
|
BlockLifetimeInfo &BlockInfo = IT.getSecond();
|
|
unsigned BBStart, BBEnd;
|
|
std::tie(BBStart, BBEnd) = BlockInstRange[BB];
|
|
|
|
BitVector Started, Ended;
|
|
Started.resize(NumAllocas);
|
|
Ended.resize(NumAllocas);
|
|
SmallVector<unsigned, 8> Start;
|
|
Start.resize(NumAllocas);
|
|
|
|
// LiveIn ranges start at the first instruction.
|
|
for (unsigned AllocaNo = 0; AllocaNo < NumAllocas; ++AllocaNo) {
|
|
if (BlockInfo.LiveIn.test(AllocaNo)) {
|
|
Started.set(AllocaNo);
|
|
Start[AllocaNo] = BBStart;
|
|
}
|
|
}
|
|
|
|
for (auto &It : BBMarkers[BB]) {
|
|
unsigned InstNo = It.first;
|
|
bool IsStart = It.second.IsStart;
|
|
unsigned AllocaNo = It.second.AllocaNo;
|
|
|
|
if (IsStart) {
|
|
assert(!Started.test(AllocaNo) || Start[AllocaNo] == BBStart);
|
|
if (!Started.test(AllocaNo)) {
|
|
Started.set(AllocaNo);
|
|
Ended.reset(AllocaNo);
|
|
Start[AllocaNo] = InstNo;
|
|
}
|
|
} else {
|
|
assert(!Ended.test(AllocaNo));
|
|
if (Started.test(AllocaNo)) {
|
|
LiveRanges[AllocaNo].addRange(Start[AllocaNo], InstNo);
|
|
Started.reset(AllocaNo);
|
|
}
|
|
Ended.set(AllocaNo);
|
|
}
|
|
}
|
|
|
|
for (unsigned AllocaNo = 0; AllocaNo < NumAllocas; ++AllocaNo)
|
|
if (Started.test(AllocaNo))
|
|
LiveRanges[AllocaNo].addRange(Start[AllocaNo], BBEnd);
|
|
}
|
|
}
|
|
|
|
#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
|
|
LLVM_DUMP_METHOD void StackLifetime::dumpAllocas() const {
|
|
dbgs() << "Allocas:\n";
|
|
for (unsigned AllocaNo = 0; AllocaNo < NumAllocas; ++AllocaNo)
|
|
dbgs() << " " << AllocaNo << ": " << *Allocas[AllocaNo] << "\n";
|
|
}
|
|
|
|
LLVM_DUMP_METHOD void StackLifetime::dumpBlockLiveness() const {
|
|
dbgs() << "Block liveness:\n";
|
|
for (auto IT : BlockLiveness) {
|
|
const BasicBlock *BB = IT.getFirst();
|
|
const BlockLifetimeInfo &BlockInfo = BlockLiveness.find(BB)->getSecond();
|
|
auto BlockRange = BlockInstRange.find(BB)->getSecond();
|
|
dbgs() << " BB (" << BB->getName() << ") [" << BlockRange.first << ", " << BlockRange.second
|
|
<< "): begin " << BlockInfo.Begin << ", end " << BlockInfo.End
|
|
<< ", livein " << BlockInfo.LiveIn << ", liveout "
|
|
<< BlockInfo.LiveOut << "\n";
|
|
}
|
|
}
|
|
|
|
LLVM_DUMP_METHOD void StackLifetime::dumpLiveRanges() const {
|
|
dbgs() << "Alloca liveness:\n";
|
|
for (unsigned AllocaNo = 0; AllocaNo < NumAllocas; ++AllocaNo)
|
|
dbgs() << " " << AllocaNo << ": " << LiveRanges[AllocaNo] << "\n";
|
|
}
|
|
#endif
|
|
|
|
StackLifetime::StackLifetime(const Function &F,
|
|
ArrayRef<const AllocaInst *> Allocas,
|
|
LivenessType Type)
|
|
: F(F), Type(Type), Allocas(Allocas), NumAllocas(Allocas.size()) {
|
|
LLVM_DEBUG(dumpAllocas());
|
|
|
|
for (unsigned I = 0; I < NumAllocas; ++I)
|
|
AllocaNumbering[Allocas[I]] = I;
|
|
|
|
collectMarkers();
|
|
}
|
|
|
|
void StackLifetime::run() {
|
|
if (HasUnknownLifetimeStartOrEnd) {
|
|
// There is marker which we can't assign to a specific alloca, so we
|
|
// fallback to the most conservative results for the type.
|
|
switch (Type) {
|
|
case LivenessType::May:
|
|
LiveRanges.resize(NumAllocas, getFullLiveRange());
|
|
break;
|
|
case LivenessType::Must:
|
|
LiveRanges.resize(NumAllocas, LiveRange(Instructions.size()));
|
|
break;
|
|
}
|
|
return;
|
|
}
|
|
|
|
LiveRanges.resize(NumAllocas, LiveRange(Instructions.size()));
|
|
for (unsigned I = 0; I < NumAllocas; ++I)
|
|
if (!InterestingAllocas.test(I))
|
|
LiveRanges[I] = getFullLiveRange();
|
|
|
|
calculateLocalLiveness();
|
|
LLVM_DEBUG(dumpBlockLiveness());
|
|
calculateLiveIntervals();
|
|
LLVM_DEBUG(dumpLiveRanges());
|
|
}
|
|
|
|
class StackLifetime::LifetimeAnnotationWriter
|
|
: public AssemblyAnnotationWriter {
|
|
const StackLifetime &SL;
|
|
|
|
void printInstrAlive(unsigned InstrNo, formatted_raw_ostream &OS) {
|
|
SmallVector<StringRef, 16> Names;
|
|
for (const auto &KV : SL.AllocaNumbering) {
|
|
if (SL.LiveRanges[KV.getSecond()].test(InstrNo))
|
|
Names.push_back(KV.getFirst()->getName());
|
|
}
|
|
llvm::sort(Names);
|
|
OS << " ; Alive: <" << llvm::join(Names, " ") << ">\n";
|
|
}
|
|
|
|
void emitBasicBlockStartAnnot(const BasicBlock *BB,
|
|
formatted_raw_ostream &OS) override {
|
|
auto ItBB = SL.BlockInstRange.find(BB);
|
|
if (ItBB == SL.BlockInstRange.end())
|
|
return; // Unreachable.
|
|
printInstrAlive(ItBB->getSecond().first, OS);
|
|
}
|
|
|
|
void printInfoComment(const Value &V, formatted_raw_ostream &OS) override {
|
|
const Instruction *Instr = dyn_cast<Instruction>(&V);
|
|
if (!Instr || !SL.isReachable(Instr))
|
|
return;
|
|
|
|
SmallVector<StringRef, 16> Names;
|
|
for (const auto &KV : SL.AllocaNumbering) {
|
|
if (SL.isAliveAfter(KV.getFirst(), Instr))
|
|
Names.push_back(KV.getFirst()->getName());
|
|
}
|
|
llvm::sort(Names);
|
|
OS << "\n ; Alive: <" << llvm::join(Names, " ") << ">\n";
|
|
}
|
|
|
|
public:
|
|
LifetimeAnnotationWriter(const StackLifetime &SL) : SL(SL) {}
|
|
};
|
|
|
|
void StackLifetime::print(raw_ostream &OS) {
|
|
LifetimeAnnotationWriter AAW(*this);
|
|
F.print(OS, &AAW);
|
|
}
|
|
|
|
PreservedAnalyses StackLifetimePrinterPass::run(Function &F,
|
|
FunctionAnalysisManager &AM) {
|
|
SmallVector<const AllocaInst *, 8> Allocas;
|
|
for (auto &I : instructions(F))
|
|
if (const AllocaInst *AI = dyn_cast<AllocaInst>(&I))
|
|
Allocas.push_back(AI);
|
|
StackLifetime SL(F, Allocas, Type);
|
|
SL.run();
|
|
SL.print(OS);
|
|
return PreservedAnalyses::all();
|
|
}
|