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AccessEnforcementOpts continued refactoring #19140

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Sep 5, 2018
Merged

AccessEnforcementOpts continued refactoring #19140

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132 changes: 73 additions & 59 deletions lib/SILOptimizer/Transforms/AccessEnforcementOpts.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -142,13 +142,13 @@ namespace {
/// Reachability results are stored here because very few accesses are
/// typically in-progress at a particular program point,
/// particularly at block boundaries.
using DenseAccessVec = llvm::SmallSetVector<BeginAccessInst *, 4>;
using DenseAccessSet = llvm::SmallSetVector<BeginAccessInst *, 4>;

// Tracks the local data flow result for a basic block
struct RegionInfo {
struct AccessSummary {
// The actual begin_access instructions
DenseAccessVec conflictFreeAccesses;
DenseAccessSet conflictFreeAccesses;
// Flag to Indicate if we started a merging process
bool merged;
AccessSummary(unsigned size) : merged(false) {}
Expand All @@ -170,11 +170,11 @@ struct RegionInfo {
unidentifiedAccess = false;
}

const DenseAccessVec &getInScopeAccesses() {
const DenseAccessSet &getInScopeAccesses() {
return inScopeConflictFreeAccesses.conflictFreeAccesses;
}

const DenseAccessVec &getOutOfScopeAccesses() {
const DenseAccessSet &getOutOfScopeAccesses() {
return outOfScopeConflictFreeAccesses.conflictFreeAccesses;
}
};
Expand Down Expand Up @@ -321,26 +321,23 @@ class AccessConflictAndMergeAnalysis {
RegionInfo::AccessSummary &accessStruct,
const AccessedStorage &storage, bool isInScope);
void visitSetForConflicts(
const DenseAccessVec &accessSet, RegionInfo &info,
const DenseAccessSet &accessSet, RegionInfo &info,
AccessConflictAndMergeAnalysis::AccessedStorageSet &loopStorage);
void
detectApplyConflicts(const swift::FunctionAccessedStorage &callSiteAccesses,
const DenseAccessVec &conflictFreeSet,
const DenseAccessSet &conflictFreeSet,
const swift::FullApplySite &fullApply, RegionInfo &info);

void detectMayReleaseConflicts(const DenseAccessVec &conflictFreeSet,
void detectMayReleaseConflicts(const DenseAccessSet &conflictFreeSet,
SILInstruction *instr, RegionInfo &info);
};
} // namespace

void AccessConflictAndMergeAnalysis::addInScopeAccess(
RegionInfo &info, BeginAccessInst *beginAccess) {
assert(
std::find(info.inScopeConflictFreeAccesses.conflictFreeAccesses.begin(),
info.inScopeConflictFreeAccesses.conflictFreeAccesses.end(),
beginAccess) ==
info.inScopeConflictFreeAccesses.conflictFreeAccesses.end() &&
"the begin_access should not have been in Vec.");
assert(info.inScopeConflictFreeAccesses.conflictFreeAccesses.count(
beginAccess) == 0 &&
"the begin_access should not have been in Vec.");
info.inScopeConflictFreeAccesses.conflictFreeAccesses.insert(beginAccess);
}

Expand Down Expand Up @@ -451,9 +448,7 @@ void AccessConflictAndMergeAnalysis::mergeAccessStruct(
}

auto pred = [&](BeginAccessInst *it) {
auto rhsIt = std::find(RHSAccessStruct.conflictFreeAccesses.begin(),
RHSAccessStruct.conflictFreeAccesses.end(), it);
return rhsIt == RHSAccessStruct.conflictFreeAccesses.end();
return RHSAccessStruct.conflictFreeAccesses.count(it) == 0;
};
accessStruct.conflictFreeAccesses.remove_if(pred);
}
Expand Down Expand Up @@ -630,23 +625,30 @@ void AccessConflictAndMergeAnalysis::visitBeginAccess(
}
SILAccessKind beginAccessKind = beginAccess->getAccessKind();
// check the current in-scope accesses for conflicts:
for (auto *outerBeginAccess : info.getInScopeAccesses()) {
// If both are reads, keep the mapped access.
if (!accessKindMayConflict(beginAccessKind,
outerBeginAccess->getAccessKind())) {
continue;
}
bool changed = false;
do {
changed = false;
for (auto *outerBeginAccess : info.getInScopeAccesses()) {
// If both are reads, keep the mapped access.
if (!accessKindMayConflict(beginAccessKind,
outerBeginAccess->getAccessKind())) {
continue;
}

auto &outerAccessInfo = result.getAccessInfo(outerBeginAccess);
// If there is no potential conflict, leave the outer access mapped.
if (!outerAccessInfo.isDistinctFrom(beginAccessInfo))
continue;
auto &outerAccessInfo = result.getAccessInfo(outerBeginAccess);
// If there is no potential conflict, leave the outer access mapped.
if (!outerAccessInfo.isDistinctFrom(beginAccessInfo))
continue;

LLVM_DEBUG(beginAccessInfo.dump(); llvm::dbgs() << " may conflict with:\n";
outerAccessInfo.dump());
LLVM_DEBUG(beginAccessInfo.dump();
llvm::dbgs() << " may conflict with:\n";
outerAccessInfo.dump());

recordConflict(info, outerAccessInfo);
}
recordConflict(info, outerAccessInfo);
changed = true;
break;
}
} while (changed);

// Record the current access to InScopeAccesses.
// It can potentially be folded
Expand Down Expand Up @@ -679,22 +681,28 @@ void AccessConflictAndMergeAnalysis::visitEndAccess(EndAccessInst *endAccess,

void AccessConflictAndMergeAnalysis::detectApplyConflicts(
const swift::FunctionAccessedStorage &callSiteAccesses,
const DenseAccessVec &conflictFreeSet,
const DenseAccessSet &conflictFreeSet,
const swift::FullApplySite &fullApply, RegionInfo &info) {
for (auto *outerBeginAccess : conflictFreeSet) {
// If there is no potential conflict, leave the outer access mapped.
SILAccessKind accessKind = outerBeginAccess->getAccessKind();
AccessInfo &outerAccessInfo = result.getAccessInfo(outerBeginAccess);
if (!callSiteAccesses.mayConflictWith(accessKind, outerAccessInfo))
continue;
bool changed = false;
do {
changed = false;
for (auto *outerBeginAccess : conflictFreeSet) {
// If there is no potential conflict, leave the outer access mapped.
SILAccessKind accessKind = outerBeginAccess->getAccessKind();
AccessInfo &outerAccessInfo = result.getAccessInfo(outerBeginAccess);
if (!callSiteAccesses.mayConflictWith(accessKind, outerAccessInfo))
continue;

LLVM_DEBUG(
llvm::dbgs() << *fullApply.getInstruction() << " call site access: ";
callSiteAccesses.dump(); llvm::dbgs() << " may conflict with:\n";
outerAccessInfo.dump());
LLVM_DEBUG(
llvm::dbgs() << *fullApply.getInstruction() << " call site access: ";
callSiteAccesses.dump(); llvm::dbgs() << " may conflict with:\n";
outerAccessInfo.dump());

recordConflict(info, outerAccessInfo);
}
recordConflict(info, outerAccessInfo);
changed = true;
break;
}
} while (changed);
}

void AccessConflictAndMergeAnalysis::visitFullApply(FullApplySite fullApply,
Expand All @@ -709,26 +717,32 @@ void AccessConflictAndMergeAnalysis::visitFullApply(FullApplySite fullApply,
}

void AccessConflictAndMergeAnalysis::detectMayReleaseConflicts(
const DenseAccessVec &conflictFreeSet, SILInstruction *instr,
const DenseAccessSet &conflictFreeSet, SILInstruction *instr,
RegionInfo &info) {
// TODO Introduce "Pure Swift" deinitializers
// We can then make use of alias information for instr's operands
// If they don't alias - we might get away with not recording a conflict
for (auto *outerBeginAccess : conflictFreeSet) {
// Only class and global access that may alias would conflict
AccessInfo &outerAccessInfo = result.getAccessInfo(outerBeginAccess);
const AccessedStorage::Kind outerKind = outerAccessInfo.getKind();
if (outerKind != AccessedStorage::Class &&
outerKind != AccessedStorage::Global) {
continue;
bool changed = false;
do {
changed = false;
for (auto *outerBeginAccess : conflictFreeSet) {
// Only class and global access that may alias would conflict
AccessInfo &outerAccessInfo = result.getAccessInfo(outerBeginAccess);
const AccessedStorage::Kind outerKind = outerAccessInfo.getKind();
if (outerKind != AccessedStorage::Class &&
outerKind != AccessedStorage::Global) {
continue;
}
// We can't prove what the deinitializer might do
// TODO Introduce "Pure Swift" deinitializers
LLVM_DEBUG(llvm::dbgs() << "MayRelease Instruction: " << *instr
<< " may conflict with:\n";
outerAccessInfo.dump());
recordConflict(info, outerAccessInfo);
changed = true;
break;
}
// We can't prove what the deinitializer might do
// TODO Introduce "Pure Swift" deinitializers
LLVM_DEBUG(llvm::dbgs() << "MayRelease Instruction: " << *instr
<< " may conflict with:\n";
outerAccessInfo.dump());
recordConflict(info, outerAccessInfo);
}
} while (changed);
}

void AccessConflictAndMergeAnalysis::visitMayRelease(SILInstruction *instr,
Expand Down Expand Up @@ -776,7 +790,7 @@ void AccessConflictAndMergeAnalysis::mergePredAccesses(
}

void AccessConflictAndMergeAnalysis::visitSetForConflicts(
const DenseAccessVec &accessSet, RegionInfo &info,
const DenseAccessSet &accessSet, RegionInfo &info,
AccessConflictAndMergeAnalysis::AccessedStorageSet &loopStorage) {
bool changed = false;
do {
Expand Down