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//===- RegionPass.cpp - Region Pass and Region Pass Manager ---------------===//
//
// 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 RegionPass and RGPassManager. All region optimization
// and transformation passes are derived from RegionPass. RGPassManager is
// responsible for managing RegionPasses.
// Most of this code has been COPIED from LoopPass.cpp
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/RegionPass.h"
#include "llvm/IR/OptBisect.h"
#include "llvm/IR/PassTimingInfo.h"
#include "llvm/IR/StructuralHash.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/Timer.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DEBUG_TYPE "regionpassmgr"
//===----------------------------------------------------------------------===//
// RGPassManager
//
char RGPassManager::ID = 0;
RGPassManager::RGPassManager()
: FunctionPass(ID), PMDataManager() {
RI = nullptr;
CurrentRegion = nullptr;
}
// Recurse through all subregions and all regions into RQ.
static void addRegionIntoQueue(Region &R, std::deque<Region *> &RQ) {
RQ.push_back(&R);
for (const auto &E : R)
addRegionIntoQueue(*E, RQ);
}
/// Pass Manager itself does not invalidate any analysis info.
void RGPassManager::getAnalysisUsage(AnalysisUsage &Info) const {
Info.addRequired<RegionInfoPass>();
Info.setPreservesAll();
}
/// run - Execute all of the passes scheduled for execution. Keep track of
/// whether any of the passes modifies the function, and if so, return true.
bool RGPassManager::runOnFunction(Function &F) {
RI = &getAnalysis<RegionInfoPass>().getRegionInfo();
bool Changed = false;
// Collect inherited analysis from Module level pass manager.
populateInheritedAnalysis(TPM->activeStack);
addRegionIntoQueue(*RI->getTopLevelRegion(), RQ);
if (RQ.empty()) // No regions, skip calling finalizers
return false;
// Initialization
for (Region *R : RQ) {
for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
RegionPass *RP = (RegionPass *)getContainedPass(Index);
Changed |= RP->doInitialization(R, *this);
}
}
// Walk Regions
while (!RQ.empty()) {
CurrentRegion = RQ.back();
// Run all passes on the current Region.
for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
RegionPass *P = (RegionPass*)getContainedPass(Index);
if (isPassDebuggingExecutionsOrMore()) {
dumpPassInfo(P, EXECUTION_MSG, ON_REGION_MSG,
CurrentRegion->getNameStr());
dumpRequiredSet(P);
}
initializeAnalysisImpl(P);
bool LocalChanged = false;
{
PassManagerPrettyStackEntry X(P, *CurrentRegion->getEntry());
TimeRegion PassTimer(getPassTimer(P));
#ifdef EXPENSIVE_CHECKS
uint64_t RefHash = StructuralHash(F);
#endif
LocalChanged = P->runOnRegion(CurrentRegion, *this);
#ifdef EXPENSIVE_CHECKS
if (!LocalChanged && (RefHash != StructuralHash(F))) {
llvm::errs() << "Pass modifies its input and doesn't report it: "
<< P->getPassName() << "\n";
llvm_unreachable("Pass modifies its input and doesn't report it");
}
#endif
Changed |= LocalChanged;
}
if (isPassDebuggingExecutionsOrMore()) {
if (LocalChanged)
dumpPassInfo(P, MODIFICATION_MSG, ON_REGION_MSG,
CurrentRegion->getNameStr());
dumpPreservedSet(P);
}
// Manually check that this region is still healthy. This is done
// instead of relying on RegionInfo::verifyRegion since RegionInfo
// is a function pass and it's really expensive to verify every
// Region in the function every time. That level of checking can be
// enabled with the -verify-region-info option.
{
TimeRegion PassTimer(getPassTimer(P));
CurrentRegion->verifyRegion();
}
// Then call the regular verifyAnalysis functions.
verifyPreservedAnalysis(P);
if (LocalChanged)
removeNotPreservedAnalysis(P);
recordAvailableAnalysis(P);
removeDeadPasses(P,
(!isPassDebuggingExecutionsOrMore())
? "<deleted>"
: CurrentRegion->getNameStr(),
ON_REGION_MSG);
}
// Pop the region from queue after running all passes.
RQ.pop_back();
// Free all region nodes created in region passes.
RI->clearNodeCache();
}
// Finalization
for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
RegionPass *P = (RegionPass*)getContainedPass(Index);
Changed |= P->doFinalization();
}
// Print the region tree after all pass.
LLVM_DEBUG(dbgs() << "\nRegion tree of function " << F.getName()
<< " after all region Pass:\n";
RI->dump(); dbgs() << "\n";);
return Changed;
}
/// Print passes managed by this manager
void RGPassManager::dumpPassStructure(unsigned Offset) {
errs().indent(Offset*2) << "Region Pass Manager\n";
for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
Pass *P = getContainedPass(Index);
P->dumpPassStructure(Offset + 1);
dumpLastUses(P, Offset+1);
}
}
namespace {
//===----------------------------------------------------------------------===//
// PrintRegionPass
class PrintRegionPass : public RegionPass {
private:
std::string Banner;
raw_ostream &Out; // raw_ostream to print on.
public:
static char ID;
PrintRegionPass(const std::string &B, raw_ostream &o)
: RegionPass(ID), Banner(B), Out(o) {}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.setPreservesAll();
}
bool runOnRegion(Region *R, RGPassManager &RGM) override {
Out << Banner;
for (const auto *BB : R->blocks()) {
if (BB)
BB->print(Out);
else
Out << "Printing <null> Block";
}
return false;
}
StringRef getPassName() const override { return "Print Region IR"; }
};
char PrintRegionPass::ID = 0;
} //end anonymous namespace
//===----------------------------------------------------------------------===//
// RegionPass
// Check if this pass is suitable for the current RGPassManager, if
// available. This pass P is not suitable for a RGPassManager if P
// is not preserving higher level analysis info used by other
// RGPassManager passes. In such case, pop RGPassManager from the
// stack. This will force assignPassManager() to create new
// LPPassManger as expected.
void RegionPass::preparePassManager(PMStack &PMS) {
// Find RGPassManager
while (!PMS.empty() &&
PMS.top()->getPassManagerType() > PMT_RegionPassManager)
PMS.pop();
// If this pass is destroying high level information that is used
// by other passes that are managed by LPM then do not insert
// this pass in current LPM. Use new RGPassManager.
if (PMS.top()->getPassManagerType() == PMT_RegionPassManager &&
!PMS.top()->preserveHigherLevelAnalysis(this))
PMS.pop();
}
/// Assign pass manager to manage this pass.
void RegionPass::assignPassManager(PMStack &PMS,
PassManagerType PreferredType) {
// Find RGPassManager
while (!PMS.empty() &&
PMS.top()->getPassManagerType() > PMT_RegionPassManager)
PMS.pop();
RGPassManager *RGPM;
// Create new Region Pass Manager if it does not exist.
if (PMS.top()->getPassManagerType() == PMT_RegionPassManager)
RGPM = (RGPassManager*)PMS.top();
else {
assert (!PMS.empty() && "Unable to create Region Pass Manager");
PMDataManager *PMD = PMS.top();
// [1] Create new Region Pass Manager
RGPM = new RGPassManager();
RGPM->populateInheritedAnalysis(PMS);
// [2] Set up new manager's top level manager
PMTopLevelManager *TPM = PMD->getTopLevelManager();
TPM->addIndirectPassManager(RGPM);
// [3] Assign manager to manage this new manager. This may create
// and push new managers into PMS
TPM->schedulePass(RGPM);
// [4] Push new manager into PMS
PMS.push(RGPM);
}
RGPM->add(this);
}
/// Get the printer pass
Pass *RegionPass::createPrinterPass(raw_ostream &O,
const std::string &Banner) const {
return new PrintRegionPass(Banner, O);
}
static std::string getDescription(const Region &R) {
return "region";
}
bool RegionPass::skipRegion(Region &R) const {
Function &F = *R.getEntry()->getParent();
OptPassGate &Gate = F.getContext().getOptPassGate();
if (Gate.isEnabled() && !Gate.shouldRunPass(this, getDescription(R)))
return true;
if (F.hasOptNone()) {
// Report this only once per function.
if (R.getEntry() == &F.getEntryBlock())
LLVM_DEBUG(dbgs() << "Skipping pass '" << getPassName()
<< "' on function " << F.getName() << "\n");
return true;
}
return false;
}