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-rw-r--r--clang/lib/Analysis/ExprMutationAnalyzer.cpp10
-rw-r--r--clang/lib/Analysis/LifetimeSafety/Dataflow.h14
-rw-r--r--clang/lib/Analysis/LifetimeSafety/Facts.cpp15
-rw-r--r--clang/lib/Analysis/LifetimeSafety/FactsGenerator.cpp2
-rw-r--r--clang/lib/Analysis/LifetimeSafety/LifetimeSafety.cpp1
-rw-r--r--clang/lib/Analysis/LifetimeSafety/LiveOrigins.cpp2
-rw-r--r--clang/lib/Analysis/LifetimeSafety/LoanPropagation.cpp135
7 files changed, 140 insertions, 39 deletions
diff --git a/clang/lib/Analysis/ExprMutationAnalyzer.cpp b/clang/lib/Analysis/ExprMutationAnalyzer.cpp
index 54c30c0..2f40c7e 100644
--- a/clang/lib/Analysis/ExprMutationAnalyzer.cpp
+++ b/clang/lib/Analysis/ExprMutationAnalyzer.cpp
@@ -238,10 +238,12 @@ const auto isMoveOnly = [] {
};
template <class T> struct NodeID;
-template <> struct NodeID<Expr> { static constexpr StringRef value = "expr"; };
-template <> struct NodeID<Decl> { static constexpr StringRef value = "decl"; };
-constexpr StringRef NodeID<Expr>::value;
-constexpr StringRef NodeID<Decl>::value;
+template <> struct NodeID<Expr> {
+ static constexpr StringRef value = "expr";
+};
+template <> struct NodeID<Decl> {
+ static constexpr StringRef value = "decl";
+};
template <class T,
class F = const Stmt *(ExprMutationAnalyzer::Analyzer::*)(const T *)>
diff --git a/clang/lib/Analysis/LifetimeSafety/Dataflow.h b/clang/lib/Analysis/LifetimeSafety/Dataflow.h
index 2f7bcb6..de821bb 100644
--- a/clang/lib/Analysis/LifetimeSafety/Dataflow.h
+++ b/clang/lib/Analysis/LifetimeSafety/Dataflow.h
@@ -67,10 +67,10 @@ private:
llvm::DenseMap<const CFGBlock *, Lattice> InStates;
/// The dataflow state after a basic block is processed.
llvm::DenseMap<const CFGBlock *, Lattice> OutStates;
- /// The dataflow state at a Program Point.
+ /// Dataflow state at each program point, indexed by Fact ID.
/// In a forward analysis, this is the state after the Fact at that point has
/// been applied, while in a backward analysis, it is the state before.
- llvm::DenseMap<ProgramPoint, Lattice> PerPointStates;
+ llvm::SmallVector<Lattice> PointToState;
static constexpr bool isForward() { return Dir == Direction::Forward; }
@@ -86,6 +86,8 @@ public:
Derived &D = static_cast<Derived &>(*this);
llvm::TimeTraceScope Time(D.getAnalysisName());
+ PointToState.resize(FactMgr.getNumFacts());
+
using Worklist =
std::conditional_t<Dir == Direction::Forward, ForwardDataflowWorklist,
BackwardDataflowWorklist>;
@@ -116,7 +118,9 @@ public:
}
protected:
- Lattice getState(ProgramPoint P) const { return PerPointStates.lookup(P); }
+ Lattice getState(ProgramPoint P) const {
+ return PointToState[P->getID().Value];
+ }
std::optional<Lattice> getInState(const CFGBlock *B) const {
auto It = InStates.find(B);
@@ -144,12 +148,12 @@ private:
if constexpr (isForward()) {
for (const Fact *F : Facts) {
State = transferFact(State, F);
- PerPointStates[F] = State;
+ PointToState[F->getID().Value] = State;
}
} else {
for (const Fact *F : llvm::reverse(Facts)) {
// In backward analysis, capture the state before applying the fact.
- PerPointStates[F] = State;
+ PointToState[F->getID().Value] = State;
State = transferFact(State, F);
}
}
diff --git a/clang/lib/Analysis/LifetimeSafety/Facts.cpp b/clang/lib/Analysis/LifetimeSafety/Facts.cpp
index 1aea64f..4a4172f 100644
--- a/clang/lib/Analysis/LifetimeSafety/Facts.cpp
+++ b/clang/lib/Analysis/LifetimeSafety/Facts.cpp
@@ -53,7 +53,7 @@ void ReturnOfOriginFact::dump(llvm::raw_ostream &OS, const LoanManager &,
void UseFact::dump(llvm::raw_ostream &OS, const LoanManager &,
const OriginManager &OM) const {
OS << "Use (";
- OM.dump(getUsedOrigin(OM), OS);
+ OM.dump(getUsedOrigin(), OS);
OS << ", " << (isWritten() ? "Write" : "Read") << ")\n";
}
@@ -64,8 +64,8 @@ void TestPointFact::dump(llvm::raw_ostream &OS, const LoanManager &,
llvm::StringMap<ProgramPoint> FactManager::getTestPoints() const {
llvm::StringMap<ProgramPoint> AnnotationToPointMap;
- for (const CFGBlock *Block : BlockToFactsMap.keys()) {
- for (const Fact *F : getFacts(Block)) {
+ for (const auto &BlockFacts : BlockToFacts) {
+ for (const Fact *F : BlockFacts) {
if (const auto *TPF = F->getAs<TestPointFact>()) {
StringRef PointName = TPF->getAnnotation();
assert(AnnotationToPointMap.find(PointName) ==
@@ -88,12 +88,9 @@ void FactManager::dump(const CFG &Cfg, AnalysisDeclContext &AC) const {
// Print blocks in the order as they appear in code for a stable ordering.
for (const CFGBlock *B : *AC.getAnalysis<PostOrderCFGView>()) {
llvm::dbgs() << " Block B" << B->getBlockID() << ":\n";
- auto It = BlockToFactsMap.find(B);
- if (It != BlockToFactsMap.end()) {
- for (const Fact *F : It->second) {
- llvm::dbgs() << " ";
- F->dump(llvm::dbgs(), LoanMgr, OriginMgr);
- }
+ for (const Fact *F : getFacts(B)) {
+ llvm::dbgs() << " ";
+ F->dump(llvm::dbgs(), LoanMgr, OriginMgr);
}
llvm::dbgs() << " End of Block\n";
}
diff --git a/clang/lib/Analysis/LifetimeSafety/FactsGenerator.cpp b/clang/lib/Analysis/LifetimeSafety/FactsGenerator.cpp
index 9b68de1..bec8e1d 100644
--- a/clang/lib/Analysis/LifetimeSafety/FactsGenerator.cpp
+++ b/clang/lib/Analysis/LifetimeSafety/FactsGenerator.cpp
@@ -333,7 +333,7 @@ void FactsGenerator::handleAssignment(const Expr *LHSExpr,
// (e.g. on the left-hand side of an assignment).
void FactsGenerator::handleUse(const DeclRefExpr *DRE) {
if (isPointerType(DRE->getType())) {
- UseFact *UF = FactMgr.createFact<UseFact>(DRE);
+ UseFact *UF = FactMgr.createFact<UseFact>(DRE, FactMgr.getOriginMgr());
CurrentBlockFacts.push_back(UF);
assert(!UseFacts.contains(DRE));
UseFacts[DRE] = UF;
diff --git a/clang/lib/Analysis/LifetimeSafety/LifetimeSafety.cpp b/clang/lib/Analysis/LifetimeSafety/LifetimeSafety.cpp
index 00c7ed90..a51ba42 100644
--- a/clang/lib/Analysis/LifetimeSafety/LifetimeSafety.cpp
+++ b/clang/lib/Analysis/LifetimeSafety/LifetimeSafety.cpp
@@ -41,6 +41,7 @@ void LifetimeSafetyAnalysis::run() {
const CFG &Cfg = *AC.getCFG();
DEBUG_WITH_TYPE("PrintCFG", Cfg.dump(AC.getASTContext().getLangOpts(),
/*ShowColors=*/true));
+ FactMgr.init(Cfg);
FactsGenerator FactGen(FactMgr, AC);
FactGen.run();
diff --git a/clang/lib/Analysis/LifetimeSafety/LiveOrigins.cpp b/clang/lib/Analysis/LifetimeSafety/LiveOrigins.cpp
index cddb3f3c..59f594e 100644
--- a/clang/lib/Analysis/LifetimeSafety/LiveOrigins.cpp
+++ b/clang/lib/Analysis/LifetimeSafety/LiveOrigins.cpp
@@ -111,7 +111,7 @@ public:
/// dominates this program point. A write operation kills the liveness of
/// the origin since it overwrites the value.
Lattice transfer(Lattice In, const UseFact &UF) {
- OriginID OID = UF.getUsedOrigin(FactMgr.getOriginMgr());
+ OriginID OID = UF.getUsedOrigin();
// Write kills liveness.
if (UF.isWritten())
return Lattice(Factory.remove(In.LiveOrigins, OID));
diff --git a/clang/lib/Analysis/LifetimeSafety/LoanPropagation.cpp b/clang/lib/Analysis/LifetimeSafety/LoanPropagation.cpp
index 387097e..0e6c194 100644
--- a/clang/lib/Analysis/LifetimeSafety/LoanPropagation.cpp
+++ b/clang/lib/Analysis/LifetimeSafety/LoanPropagation.cpp
@@ -5,36 +5,114 @@
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
-#include "clang/Analysis/Analyses/LifetimeSafety/LoanPropagation.h"
-#include "Dataflow.h"
+#include <cassert>
#include <memory>
+#include "Dataflow.h"
+#include "clang/Analysis/Analyses/LifetimeSafety/Facts.h"
+#include "clang/Analysis/Analyses/LifetimeSafety/LoanPropagation.h"
+#include "clang/Analysis/Analyses/LifetimeSafety/Loans.h"
+#include "clang/Analysis/Analyses/LifetimeSafety/Origins.h"
+#include "clang/Analysis/Analyses/LifetimeSafety/Utils.h"
+#include "clang/Analysis/AnalysisDeclContext.h"
+#include "clang/Analysis/CFG.h"
+#include "clang/Basic/LLVM.h"
+#include "llvm/ADT/BitVector.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Support/TimeProfiler.h"
+#include "llvm/Support/raw_ostream.h"
+
namespace clang::lifetimes::internal {
+
+// Prepass to find persistent origins. An origin is persistent if it is
+// referenced in more than one basic block.
+static llvm::BitVector computePersistentOrigins(const FactManager &FactMgr,
+ const CFG &C) {
+ llvm::TimeTraceScope("ComputePersistentOrigins");
+ unsigned NumOrigins = FactMgr.getOriginMgr().getNumOrigins();
+ llvm::BitVector PersistentOrigins(NumOrigins);
+
+ llvm::SmallVector<const CFGBlock *> OriginToFirstSeenBlock(NumOrigins,
+ nullptr);
+ for (const CFGBlock *B : C) {
+ for (const Fact *F : FactMgr.getFacts(B)) {
+ auto CheckOrigin = [&](OriginID OID) {
+ if (PersistentOrigins.test(OID.Value))
+ return;
+ auto &FirstSeenBlock = OriginToFirstSeenBlock[OID.Value];
+ if (FirstSeenBlock == nullptr)
+ FirstSeenBlock = B;
+ if (FirstSeenBlock != B) {
+ // We saw this origin in more than one block.
+ PersistentOrigins.set(OID.Value);
+ }
+ };
+
+ switch (F->getKind()) {
+ case Fact::Kind::Issue:
+ CheckOrigin(F->getAs<IssueFact>()->getOriginID());
+ break;
+ case Fact::Kind::OriginFlow: {
+ const auto *OF = F->getAs<OriginFlowFact>();
+ CheckOrigin(OF->getDestOriginID());
+ CheckOrigin(OF->getSrcOriginID());
+ break;
+ }
+ case Fact::Kind::ReturnOfOrigin:
+ CheckOrigin(F->getAs<ReturnOfOriginFact>()->getReturnedOriginID());
+ break;
+ case Fact::Kind::Use:
+ CheckOrigin(F->getAs<UseFact>()->getUsedOrigin());
+ break;
+ case Fact::Kind::Expire:
+ case Fact::Kind::TestPoint:
+ break;
+ }
+ }
+ }
+ return PersistentOrigins;
+}
+
namespace {
+
/// Represents the dataflow lattice for loan propagation.
///
/// This lattice tracks which loans each origin may hold at a given program
/// point.The lattice has a finite height: An origin's loan set is bounded by
/// the total number of loans in the function.
-/// TODO(opt): To reduce the lattice size, propagate origins of declarations,
-/// not expressions, because expressions are not visible across blocks.
struct Lattice {
/// The map from an origin to the set of loans it contains.
- OriginLoanMap Origins = OriginLoanMap(nullptr);
-
- explicit Lattice(const OriginLoanMap &S) : Origins(S) {}
+ /// Origins that appear in multiple blocks. Participates in join operations.
+ OriginLoanMap PersistentOrigins = OriginLoanMap(nullptr);
+ /// Origins confined to a single block. Discarded at block boundaries.
+ OriginLoanMap BlockLocalOrigins = OriginLoanMap(nullptr);
+
+ explicit Lattice(const OriginLoanMap &Persistent,
+ const OriginLoanMap &BlockLocal)
+ : PersistentOrigins(Persistent), BlockLocalOrigins(BlockLocal) {}
Lattice() = default;
bool operator==(const Lattice &Other) const {
- return Origins == Other.Origins;
+ return PersistentOrigins == Other.PersistentOrigins &&
+ BlockLocalOrigins == Other.BlockLocalOrigins;
}
bool operator!=(const Lattice &Other) const { return !(*this == Other); }
void dump(llvm::raw_ostream &OS) const {
OS << "LoanPropagationLattice State:\n";
- if (Origins.isEmpty())
+ OS << " Persistent Origins:\n";
+ if (PersistentOrigins.isEmpty())
OS << " <empty>\n";
- for (const auto &Entry : Origins) {
+ for (const auto &Entry : PersistentOrigins) {
+ if (Entry.second.isEmpty())
+ OS << " Origin " << Entry.first << " contains no loans\n";
+ for (const LoanID &LID : Entry.second)
+ OS << " Origin " << Entry.first << " contains Loan " << LID << "\n";
+ }
+ OS << " Block-Local Origins:\n";
+ if (BlockLocalOrigins.isEmpty())
+ OS << " <empty>\n";
+ for (const auto &Entry : BlockLocalOrigins) {
if (Entry.second.isEmpty())
OS << " Origin " << Entry.first << " contains no loans\n";
for (const LoanID &LID : Entry.second)
@@ -50,7 +128,8 @@ public:
OriginLoanMap::Factory &OriginLoanMapFactory,
LoanSet::Factory &LoanSetFactory)
: DataflowAnalysis(C, AC, F), OriginLoanMapFactory(OriginLoanMapFactory),
- LoanSetFactory(LoanSetFactory) {}
+ LoanSetFactory(LoanSetFactory),
+ PersistentOrigins(computePersistentOrigins(F, C)) {}
using Base::transfer;
@@ -59,10 +138,10 @@ public:
Lattice getInitialState() { return Lattice{}; }
/// Merges two lattices by taking the union of loans for each origin.
- // TODO(opt): Keep the state small by removing origins which become dead.
+ /// Only persistent origins are joined; block-local origins are discarded.
Lattice join(Lattice A, Lattice B) {
OriginLoanMap JoinedOrigins = utils::join(
- A.Origins, B.Origins, OriginLoanMapFactory,
+ A.PersistentOrigins, B.PersistentOrigins, OriginLoanMapFactory,
[&](const LoanSet *S1, const LoanSet *S2) {
assert((S1 || S2) && "unexpectedly merging 2 empty sets");
if (!S1)
@@ -74,16 +153,15 @@ public:
// Asymmetric join is a performance win. For origins present only on one
// branch, the loan set can be carried over as-is.
utils::JoinKind::Asymmetric);
- return Lattice(JoinedOrigins);
+ return Lattice(JoinedOrigins, OriginLoanMapFactory.getEmptyMap());
}
/// A new loan is issued to the origin. Old loans are erased.
Lattice transfer(Lattice In, const IssueFact &F) {
OriginID OID = F.getOriginID();
LoanID LID = F.getLoanID();
- return Lattice(OriginLoanMapFactory.add(
- In.Origins, OID,
- LoanSetFactory.add(LoanSetFactory.getEmptySet(), LID)));
+ LoanSet NewLoans = LoanSetFactory.add(LoanSetFactory.getEmptySet(), LID);
+ return setLoans(In, OID, NewLoans);
}
/// A flow from source to destination. If `KillDest` is true, this replaces
@@ -98,7 +176,7 @@ public:
LoanSet SrcLoans = getLoans(In, SrcOID);
LoanSet MergedLoans = utils::join(DestLoans, SrcLoans, LoanSetFactory);
- return Lattice(OriginLoanMapFactory.add(In.Origins, DestOID, MergedLoans));
+ return setLoans(In, DestOID, MergedLoans);
}
LoanSet getLoans(OriginID OID, ProgramPoint P) const {
@@ -106,14 +184,33 @@ public:
}
private:
+ /// Returns true if the origin is persistent (referenced in multiple blocks).
+ bool isPersistent(OriginID OID) const {
+ return PersistentOrigins.test(OID.Value);
+ }
+
+ Lattice setLoans(Lattice L, OriginID OID, LoanSet Loans) {
+ if (isPersistent(OID))
+ return Lattice(OriginLoanMapFactory.add(L.PersistentOrigins, OID, Loans),
+ L.BlockLocalOrigins);
+ return Lattice(L.PersistentOrigins,
+ OriginLoanMapFactory.add(L.BlockLocalOrigins, OID, Loans));
+ }
+
LoanSet getLoans(Lattice L, OriginID OID) const {
- if (auto *Loans = L.Origins.lookup(OID))
+ const OriginLoanMap *Map =
+ isPersistent(OID) ? &L.PersistentOrigins : &L.BlockLocalOrigins;
+ if (auto *Loans = Map->lookup(OID))
return *Loans;
return LoanSetFactory.getEmptySet();
}
OriginLoanMap::Factory &OriginLoanMapFactory;
LoanSet::Factory &LoanSetFactory;
+ /// Boolean vector indexed by origin ID. If true, the origin appears in
+ /// multiple basic blocks and must participate in join operations. If false,
+ /// the origin is block-local and can be discarded at block boundaries.
+ llvm::BitVector PersistentOrigins;
};
} // namespace
generated by cgit v1.1 at 2025-11-07 18:54:48 +0000