[clang][dataflow] Add synthetic fields to `RecordStorageLocation` (#73860)

Synthetic fields are intended to model the internal state of a class
(e.g. the value stored in a `std::optional`) without having to depend on
that class's implementation details.

Today, this is typically done with properties on `RecordValue`s, but
these have several drawbacks:

* Care must be taken to call `refreshRecordValue()` before modifying a
property so that the modified property values aren’t seen by other
environments that may have access to the same `RecordValue`.

* Properties aren’t associated with a storage location. If an analysis
needs to associate a location with the value stored in a property (e.g.
to model the reference returned by `std::optional::value()`), it needs
to manually add an indirection using a `PointerValue`. (See for example
the way this is done in UncheckedOptionalAccessModel.cpp, specifically
in `maybeInitializeOptionalValueMember()`.)

* Properties don’t participate in the builtin compare, join, and widen
operations. If an analysis needs to apply these operations to
properties, it needs to override the corresponding methods of
`ValueModel`.

* Longer-term, we plan to eliminate `RecordValue`, as by-value
operations on records aren’t really “a thing” in C++ (see
https://discourse.llvm.org/t/70086#changed-structvalue-api-14). This
would obviously eliminate the ability to set properties on
`RecordValue`s.

To demonstrate the advantages of synthetic fields, this patch converts
UncheckedOptionalAccessModel.cpp to synthetic fields. This greatly
simplifies the implementation of the check.

This PR is pretty big; to make it easier to review, I have broken it
down into a stack of three commits, each of which contains a set of
logically related changes. I considered submitting each of these as a
separate PR, but the commits only really make sense when taken together.

To review, I suggest first looking at the changes in
UncheckedOptionalAccessModel.cpp. This gives a flavor for how the
various API changes work together in the context of an analysis. Then,
review the rest of the changes.

7 files changed, 260 insertions, 340 deletions

diff --git a/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp b/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
index 0a2fcd4..fa11497 100644
--- a/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
+++ b/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
@@ -68,11 +68,38 @@ StorageLocation &DataflowAnalysisContext::createStorageLocation(QualType Type) {
       else
         FieldLocs.insert({Field, &createStorageLocation(
                                      Field->getType().getNonReferenceType())});
-    return arena().create<RecordStorageLocation>(Type, std::move(FieldLocs));
+
+    RecordStorageLocation::SyntheticFieldMap SyntheticFields;
+    for (const auto &Entry : getSyntheticFields(Type))
+      SyntheticFields.insert(
+          {Entry.getKey(),
+           &createStorageLocation(Entry.getValue().getNonReferenceType())});
+
+    return createRecordStorageLocation(Type, std::move(FieldLocs),
+                                       std::move(SyntheticFields));
   }
   return arena().create<ScalarStorageLocation>(Type);
 }
 
+// Returns the keys for a given `StringMap`.
+// Can't use `StringSet` as the return type as it doesn't support `operator==`.
+template <typename T>
+static llvm::DenseSet<llvm::StringRef> getKeys(const llvm::StringMap<T> &Map) {
+  return llvm::DenseSet<llvm::StringRef>(Map.keys().begin(), Map.keys().end());
+}
+
+RecordStorageLocation &DataflowAnalysisContext::createRecordStorageLocation(
+    QualType Type, RecordStorageLocation::FieldToLoc FieldLocs,
+    RecordStorageLocation::SyntheticFieldMap SyntheticFields) {
+  assert(Type->isRecordType());
+  assert(containsSameFields(getModeledFields(Type), FieldLocs));
+  assert(getKeys(getSyntheticFields(Type)) == getKeys(SyntheticFields));
+
+  RecordStorageLocationCreated = true;
+  return arena().create<RecordStorageLocation>(Type, std::move(FieldLocs),
+                                               std::move(SyntheticFields));
+}
+
 StorageLocation &
 DataflowAnalysisContext::getStableStorageLocation(const ValueDecl &D) {
   if (auto *Loc = DeclToLoc.lookup(&D))
@@ -367,3 +394,14 @@ clang::dataflow::FieldSet clang::dataflow::getObjectFields(QualType Type) {
   getFieldsFromClassHierarchy(Type, Fields);
   return Fields;
 }
+
+bool clang::dataflow::containsSameFields(
+    const clang::dataflow::FieldSet &Fields,
+    const clang::dataflow::RecordStorageLocation::FieldToLoc &FieldLocs) {
+  if (Fields.size() != FieldLocs.size())
+    return false;
+  for ([[maybe_unused]] auto [Field, Loc] : FieldLocs)
+    if (!Fields.contains(cast_or_null<FieldDecl>(Field)))
+      return false;
+  return true;
+}
diff --git a/clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp b/clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp
index 525ab18..042402a 100644
--- a/clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp
+++ b/clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp
@@ -367,6 +367,59 @@ getFieldsGlobalsAndFuncs(const Stmt &S, FieldSet &Fields,
   }
 }
 
+Environment::Environment(DataflowAnalysisContext &DACtx)
+    : DACtx(&DACtx),
+      FlowConditionToken(DACtx.arena().makeFlowConditionToken()) {}
+
+Environment::Environment(DataflowAnalysisContext &DACtx,
+                         const DeclContext &DeclCtx)
+    : Environment(DACtx) {
+  CallStack.push_back(&DeclCtx);
+}
+
+void Environment::initialize() {
+  const DeclContext *DeclCtx = getDeclCtx();
+  if (DeclCtx == nullptr)
+    return;
+
+  if (const auto *FuncDecl = dyn_cast<FunctionDecl>(DeclCtx)) {
+    assert(FuncDecl->getBody() != nullptr);
+
+    initFieldsGlobalsAndFuncs(FuncDecl);
+
+    for (const auto *ParamDecl : FuncDecl->parameters()) {
+      assert(ParamDecl != nullptr);
+      setStorageLocation(*ParamDecl, createObject(*ParamDecl, nullptr));
+    }
+  }
+
+  if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(DeclCtx)) {
+    auto *Parent = MethodDecl->getParent();
+    assert(Parent != nullptr);
+
+    if (Parent->isLambda()) {
+      for (auto Capture : Parent->captures()) {
+        if (Capture.capturesVariable()) {
+          const auto *VarDecl = Capture.getCapturedVar();
+          assert(VarDecl != nullptr);
+          setStorageLocation(*VarDecl, createObject(*VarDecl, nullptr));
+        } else if (Capture.capturesThis()) {
+          const auto *SurroundingMethodDecl =
+              cast<CXXMethodDecl>(DeclCtx->getNonClosureAncestor());
+          QualType ThisPointeeType =
+              SurroundingMethodDecl->getFunctionObjectParameterType();
+          setThisPointeeStorageLocation(
+              cast<RecordValue>(createValue(ThisPointeeType))->getLoc());
+        }
+      }
+    } else if (MethodDecl->isImplicitObjectMemberFunction()) {
+      QualType ThisPointeeType = MethodDecl->getFunctionObjectParameterType();
+      setThisPointeeStorageLocation(
+          cast<RecordValue>(createValue(ThisPointeeType))->getLoc());
+    }
+  }
+}
+
 // FIXME: Add support for resetting globals after function calls to enable
 // the implementation of sound analyses.
 void Environment::initFieldsGlobalsAndFuncs(const FunctionDecl *FuncDecl) {
@@ -416,59 +469,12 @@ void Environment::initFieldsGlobalsAndFuncs(const FunctionDecl *FuncDecl) {
   }
 }
 
-Environment::Environment(DataflowAnalysisContext &DACtx)
-    : DACtx(&DACtx),
-      FlowConditionToken(DACtx.arena().makeFlowConditionToken()) {}
-
 Environment Environment::fork() const {
   Environment Copy(*this);
   Copy.FlowConditionToken = DACtx->forkFlowCondition(FlowConditionToken);
   return Copy;
 }
 
-Environment::Environment(DataflowAnalysisContext &DACtx,
-                         const DeclContext &DeclCtx)
-    : Environment(DACtx) {
-  CallStack.push_back(&DeclCtx);
-
-  if (const auto *FuncDecl = dyn_cast<FunctionDecl>(&DeclCtx)) {
-    assert(FuncDecl->getBody() != nullptr);
-
-    initFieldsGlobalsAndFuncs(FuncDecl);
-
-    for (const auto *ParamDecl : FuncDecl->parameters()) {
-      assert(ParamDecl != nullptr);
-      setStorageLocation(*ParamDecl, createObject(*ParamDecl, nullptr));
-    }
-  }
-
-  if (const auto *MethodDecl = dyn_cast<CXXMethodDecl>(&DeclCtx)) {
-    auto *Parent = MethodDecl->getParent();
-    assert(Parent != nullptr);
-
-    if (Parent->isLambda()) {
-      for (auto Capture : Parent->captures()) {
-        if (Capture.capturesVariable()) {
-          const auto *VarDecl = Capture.getCapturedVar();
-          assert(VarDecl != nullptr);
-          setStorageLocation(*VarDecl, createObject(*VarDecl, nullptr));
-        } else if (Capture.capturesThis()) {
-          const auto *SurroundingMethodDecl =
-              cast<CXXMethodDecl>(DeclCtx.getNonClosureAncestor());
-          QualType ThisPointeeType =
-              SurroundingMethodDecl->getFunctionObjectParameterType();
-          ThisPointeeLoc =
-              &cast<RecordValue>(createValue(ThisPointeeType))->getLoc();
-        }
-      }
-    } else if (MethodDecl->isImplicitObjectMemberFunction()) {
-      QualType ThisPointeeType = MethodDecl->getFunctionObjectParameterType();
-      ThisPointeeLoc =
-          &cast<RecordValue>(createValue(ThisPointeeType))->getLoc();
-    }
-  }
-}
-
 bool Environment::canDescend(unsigned MaxDepth,
                              const DeclContext *Callee) const {
   return CallStack.size() <= MaxDepth && !llvm::is_contained(CallStack, Callee);
@@ -727,10 +733,6 @@ StorageLocation *Environment::getStorageLocation(const Expr &E) const {
   return getStorageLocationInternal(E);
 }
 
-RecordStorageLocation *Environment::getThisPointeeStorageLocation() const {
-  return ThisPointeeLoc;
-}
-
 RecordStorageLocation &
 Environment::getResultObjectLocation(const Expr &RecordPRValue) {
   assert(RecordPRValue.getType()->isRecordType());
@@ -852,8 +854,16 @@ Value *Environment::createValueUnlessSelfReferential(
                                           CreatedValuesCount)});
     }
 
-    RecordStorageLocation &Loc =
-        arena().create<RecordStorageLocation>(Type, std::move(FieldLocs));
+    RecordStorageLocation::SyntheticFieldMap SyntheticFieldLocs;
+    for (const auto &Entry : DACtx->getSyntheticFields(Type)) {
+      SyntheticFieldLocs.insert(
+          {Entry.getKey(),
+           &createLocAndMaybeValue(Entry.getValue(), Visited, Depth + 1,
+                                   CreatedValuesCount)});
+    }
+
+    RecordStorageLocation &Loc = DACtx->createRecordStorageLocation(
+        Type, std::move(FieldLocs), std::move(SyntheticFieldLocs));
     RecordValue &RecordVal = create<RecordValue>(Loc);
 
     // As we already have a storage location for the `RecordValue`, we can and
diff --git a/clang/lib/Analysis/FlowSensitive/HTMLLogger.cpp b/clang/lib/Analysis/FlowSensitive/HTMLLogger.cpp
index 8329367..7430ef5 100644
--- a/clang/lib/Analysis/FlowSensitive/HTMLLogger.cpp
+++ b/clang/lib/Analysis/FlowSensitive/HTMLLogger.cpp
@@ -136,6 +136,10 @@ public:
             if (Value *Val = Env.getValue(*Child.second))
               dump(*Val);
         });
+
+      for (const auto &SyntheticField : RLoc->synthetic_fields())
+        JOS.attributeObject(("sf:" + SyntheticField.first()).str(),
+                            [&] { dump(*SyntheticField.second); });
     }
   }
 
diff --git a/clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp b/clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
index 55d0713..69ac2c2 100644
--- a/clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
+++ b/clang/lib/Analysis/FlowSensitive/Models/UncheckedOptionalAccessModel.cpp
@@ -122,12 +122,6 @@ auto nulloptTypeDecl() {
 
 auto hasNulloptType() { return hasType(nulloptTypeDecl()); }
 
-// `optional` or `nullopt_t`
-auto hasAnyOptionalType() {
-  return hasType(hasUnqualifiedDesugaredType(
-      recordType(hasDeclaration(anyOf(nulloptTypeDecl(), optionalClass())))));
-}
-
 auto inPlaceClass() {
   return recordDecl(hasAnyName("std::in_place_t", "absl::in_place_t",
                                "base::in_place_t", "folly::in_place_t"));
@@ -162,11 +156,6 @@ auto isOptionalValueOrConversionAssignment() {
       argumentCountIs(2), hasArgument(1, unless(hasNulloptType())));
 }
 
-auto isNulloptConstructor() {
-  return cxxConstructExpr(hasNulloptType(), argumentCountIs(1),
-                          hasArgument(0, hasNulloptType()));
-}
-
 auto isOptionalNulloptAssignment() {
   return cxxOperatorCallExpr(hasOverloadedOperatorName("="),
                              callee(cxxMethodDecl(ofClass(optionalClass()))),
@@ -246,10 +235,19 @@ const Formula &forceBoolValue(Environment &Env, const Expr &Expr) {
   return Value->formula();
 }
 
+StorageLocation &locForHasValue(const RecordStorageLocation &OptionalLoc) {
+  return OptionalLoc.getSyntheticField("has_value");
+}
+
+StorageLocation &locForValue(const RecordStorageLocation &OptionalLoc) {
+  return OptionalLoc.getSyntheticField("value");
+}
+
 /// Sets `HasValueVal` as the symbolic value that represents the "has_value"
-/// property of the optional value `OptionalVal`.
-void setHasValue(Value &OptionalVal, BoolValue &HasValueVal) {
-  OptionalVal.setProperty("has_value", HasValueVal);
+/// property of the optional at `OptionalLoc`.
+void setHasValue(RecordStorageLocation &OptionalLoc, BoolValue &HasValueVal,
+                 Environment &Env) {
+  Env.setValue(locForHasValue(OptionalLoc), HasValueVal);
 }
 
 /// Creates a symbolic value for an `optional` value at an existing storage
@@ -259,23 +257,22 @@ RecordValue &createOptionalValue(RecordStorageLocation &Loc,
                                  BoolValue &HasValueVal, Environment &Env) {
   auto &OptionalVal = Env.create<RecordValue>(Loc);
   Env.setValue(Loc, OptionalVal);
-  setHasValue(OptionalVal, HasValueVal);
+  setHasValue(Loc, HasValueVal, Env);
   return OptionalVal;
 }
 
 /// Returns the symbolic value that represents the "has_value" property of the
-/// optional value `OptionalVal`. Returns null if `OptionalVal` is null.
-BoolValue *getHasValue(Environment &Env, Value *OptionalVal) {
-  if (OptionalVal != nullptr) {
-    auto *HasValueVal =
-        cast_or_null<BoolValue>(OptionalVal->getProperty("has_value"));
-    if (HasValueVal == nullptr) {
-      HasValueVal = &Env.makeAtomicBoolValue();
-      OptionalVal->setProperty("has_value", *HasValueVal);
-    }
-    return HasValueVal;
+/// optional at `OptionalLoc`. Returns null if `OptionalLoc` is null.
+BoolValue *getHasValue(Environment &Env, RecordStorageLocation *OptionalLoc) {
+  if (OptionalLoc == nullptr)
+    return nullptr;
+  StorageLocation &HasValueLoc = locForHasValue(*OptionalLoc);
+  auto *HasValueVal = cast_or_null<BoolValue>(Env.getValue(HasValueLoc));
+  if (HasValueVal == nullptr) {
+    HasValueVal = &Env.makeAtomicBoolValue();
+    Env.setValue(HasValueLoc, *HasValueVal);
   }
-  return nullptr;
+  return HasValueVal;
 }
 
 /// Returns true if and only if `Type` is an optional type.
@@ -302,155 +299,31 @@ int countOptionalWrappers(const ASTContext &ASTCtx, QualType Type) {
                      .getDesugaredType(ASTCtx));
 }
 
-/// Tries to initialize the `optional`'s value (that is, contents), and return
-/// its location. Returns nullptr if the value can't be represented.
-StorageLocation *maybeInitializeOptionalValueMember(QualType Q,
-                                                    Value &OptionalVal,
-                                                    Environment &Env) {
-  // The "value" property represents a synthetic field. As such, it needs
-  // `StorageLocation`, like normal fields (and other variables). So, we model
-  // it with a `PointerValue`, since that includes a storage location.  Once
-  // the property is set, it will be shared by all environments that access the
-  // `Value` representing the optional (here, `OptionalVal`).
-  if (auto *ValueProp = OptionalVal.getProperty("value")) {
-    auto *ValuePtr = clang::cast<PointerValue>(ValueProp);
-    auto &ValueLoc = ValuePtr->getPointeeLoc();
-    if (Env.getValue(ValueLoc) != nullptr)
-      return &ValueLoc;
-
-    // The property was previously set, but the value has been lost. This can
-    // happen in various situations, for example:
-    // - Because of an environment merge (where the two environments mapped the
-    //   property to different values, which resulted in them both being
-    //   discarded).
-    // - When two blocks in the CFG, with neither a dominator of the other,
-    //   visit the same optional value. (FIXME: This is something we can and
-    //   should fix -- see also the lengthy FIXME below.)
-    // - Or even when a block is revisited during testing to collect
-    //   per-statement state.
-    // FIXME: This situation means that the optional contents are not shared
-    // between branches and the like. Practically, this lack of sharing
-    // reduces the precision of the model when the contents are relevant to
-    // the check, like another optional or a boolean that influences control
-    // flow.
-    if (ValueLoc.getType()->isRecordType()) {
-      refreshRecordValue(cast<RecordStorageLocation>(ValueLoc), Env);
-      return &ValueLoc;
-    } else {
-      auto *ValueVal = Env.createValue(ValueLoc.getType());
-      if (ValueVal == nullptr)
-        return nullptr;
-      Env.setValue(ValueLoc, *ValueVal);
-      return &ValueLoc;
-    }
-  }
-
-  auto Ty = Q.getNonReferenceType();
-  auto &ValueLoc = Env.createObject(Ty);
-  auto &ValuePtr = Env.create<PointerValue>(ValueLoc);
-  // FIXME:
-  // The change we make to the `value` property below may become visible to
-  // other blocks that aren't successors of the current block and therefore
-  // don't see the change we made above mapping `ValueLoc` to `ValueVal`. For
-  // example:
-  //
-  //   void target(optional<int> oo, bool b) {
-  //     // `oo` is associated with a `RecordValue` here, which we will call
-  //     // `OptionalVal`.
-  //
-  //     // The `has_value` property is set on `OptionalVal` (but not the
-  //     // `value` property yet).
-  //     if (!oo.has_value()) return;
-  //
-  //     if (b) {
-  //       // Let's assume we transfer the `if` branch first.
-  //       //
-  //       // This causes us to call `maybeInitializeOptionalValueMember()`,
-  //       // which causes us to set the `value` property on `OptionalVal`
-  //       // (which had not been set until this point). This `value` property
-  //       // refers to a `PointerValue`, which in turn refers to a
-  //       // StorageLocation` that is associated to an `IntegerValue`.
-  //       oo.value();
-  //     } else {
-  //       // Let's assume we transfer the `else` branch after the `if` branch.
-  //       //
-  //       // We see the `value` property that the `if` branch set on
-  //       // `OptionalVal`, but in the environment for this block, the
-  //       // `StorageLocation` in the `PointerValue` is not associated with any
-  //       // `Value`.
-  //       oo.value();
-  //     }
-  //   }
-  //
-  // This situation is currently "saved" by the code above that checks whether
-  // the `value` property is already set, and if, the `ValueLoc` is not
-  // associated with a `ValueVal`, creates a new `ValueVal`.
-  //
-  // However, what we should really do is to make sure that the change to the
-  // `value` property does not "leak" to other blocks that are not successors
-  // of this block. To do this, instead of simply setting the `value` property
-  // on the existing `OptionalVal`, we should create a new `Value` for the
-  // optional, set the property on that, and associate the storage location that
-  // is currently associated with the existing `OptionalVal` with the newly
-  // created `Value` instead.
-  OptionalVal.setProperty("value", ValuePtr);
-  return &ValueLoc;
-}
-
-void initializeOptionalReference(const Expr *OptionalExpr,
-                                 const MatchFinder::MatchResult &,
-                                 LatticeTransferState &State) {
-  if (auto *OptionalVal = State.Env.getValue(*OptionalExpr)) {
-    if (OptionalVal->getProperty("has_value") == nullptr) {
-      setHasValue(*OptionalVal, State.Env.makeAtomicBoolValue());
-    }
+StorageLocation *getLocBehindPossiblePointer(const Expr &E,
+                                             const Environment &Env) {
+  if (E.isPRValue()) {
+    if (auto *PointerVal = dyn_cast_or_null<PointerValue>(Env.getValue(E)))
+      return &PointerVal->getPointeeLoc();
+    return nullptr;
   }
-}
-
-/// Returns true if and only if `OptionalVal` is initialized and known to be
-/// empty in `Env`.
-bool isEmptyOptional(const Value &OptionalVal, const Environment &Env) {
-  auto *HasValueVal =
-      cast_or_null<BoolValue>(OptionalVal.getProperty("has_value"));
-  return HasValueVal != nullptr &&
-         Env.proves(Env.arena().makeNot(HasValueVal->formula()));
-}
-
-/// Returns true if and only if `OptionalVal` is initialized and known to be
-/// non-empty in `Env`.
-bool isNonEmptyOptional(const Value &OptionalVal, const Environment &Env) {
-  auto *HasValueVal =
-      cast_or_null<BoolValue>(OptionalVal.getProperty("has_value"));
-  return HasValueVal != nullptr && Env.proves(HasValueVal->formula());
-}
-
-Value *getValueBehindPossiblePointer(const Expr &E, const Environment &Env) {
-  Value *Val = Env.getValue(E);
-  if (auto *PointerVal = dyn_cast_or_null<PointerValue>(Val))
-    return Env.getValue(PointerVal->getPointeeLoc());
-  return Val;
+  return Env.getStorageLocation(E);
 }
 
 void transferUnwrapCall(const Expr *UnwrapExpr, const Expr *ObjectExpr,
                         LatticeTransferState &State) {
-  if (auto *OptionalVal =
-          getValueBehindPossiblePointer(*ObjectExpr, State.Env)) {
+  if (auto *OptionalLoc = cast_or_null<RecordStorageLocation>(
+          getLocBehindPossiblePointer(*ObjectExpr, State.Env))) {
     if (State.Env.getStorageLocation(*UnwrapExpr) == nullptr)
-      if (auto *Loc = maybeInitializeOptionalValueMember(
-              UnwrapExpr->getType(), *OptionalVal, State.Env))
-        State.Env.setStorageLocation(*UnwrapExpr, *Loc);
+      State.Env.setStorageLocation(*UnwrapExpr, locForValue(*OptionalLoc));
   }
 }
 
 void transferArrowOpCall(const Expr *UnwrapExpr, const Expr *ObjectExpr,
                          LatticeTransferState &State) {
-  if (auto *OptionalVal =
-          getValueBehindPossiblePointer(*ObjectExpr, State.Env)) {
-    if (auto *Loc = maybeInitializeOptionalValueMember(
-            UnwrapExpr->getType()->getPointeeType(), *OptionalVal, State.Env)) {
-      State.Env.setValue(*UnwrapExpr, State.Env.create<PointerValue>(*Loc));
-    }
-  }
+  if (auto *OptionalLoc = cast_or_null<RecordStorageLocation>(
+          getLocBehindPossiblePointer(*ObjectExpr, State.Env)))
+    State.Env.setValue(
+        *UnwrapExpr, State.Env.create<PointerValue>(locForValue(*OptionalLoc)));
 }
 
 void transferMakeOptionalCall(const CallExpr *E,
@@ -465,8 +338,7 @@ void transferOptionalHasValueCall(const CXXMemberCallExpr *CallExpr,
                                   const MatchFinder::MatchResult &,
                                   LatticeTransferState &State) {
   if (auto *HasValueVal = getHasValue(
-          State.Env, getValueBehindPossiblePointer(
-                         *CallExpr->getImplicitObjectArgument(), State.Env))) {
+          State.Env, getImplicitObjectLocation(*CallExpr, State.Env))) {
     State.Env.setValue(*CallExpr, *HasValueVal);
   }
 }
@@ -480,12 +352,11 @@ void transferValueOrImpl(
                                 const Formula &HasValueVal)) {
   auto &Env = State.Env;
 
-  const auto *ObjectArgumentExpr =
-      Result.Nodes.getNodeAs<clang::CXXMemberCallExpr>(ValueOrCallID)
-          ->getImplicitObjectArgument();
+  const auto *MCE =
+      Result.Nodes.getNodeAs<clang::CXXMemberCallExpr>(ValueOrCallID);
 
-  auto *HasValueVal = getHasValue(
-      State.Env, getValueBehindPossiblePointer(*ObjectArgumentExpr, State.Env));
+  auto *HasValueVal =
+      getHasValue(State.Env, getImplicitObjectLocation(*MCE, State.Env));
   if (HasValueVal == nullptr)
     return;
 
@@ -578,7 +449,9 @@ BoolValue &valueOrConversionHasValue(const FunctionDecl &F, const Expr &E,
 
   // This is a constructor/assignment call for `optional<T>` with argument of
   // type `optional<U>` such that `T` is constructible from `U`.
-  if (auto *HasValueVal = getHasValue(State.Env, State.Env.getValue(E)))
+  auto *Loc =
+      cast_or_null<RecordStorageLocation>(State.Env.getStorageLocation(E));
+  if (auto *HasValueVal = getHasValue(State.Env, Loc))
     return *HasValueVal;
   return State.Env.makeAtomicBoolValue();
 }
@@ -645,11 +518,11 @@ void transferSwap(RecordStorageLocation *Loc1, RecordStorageLocation *Loc2,
   // allows for local reasoning about the value. To avoid the above, we would
   // need *lazy* value allocation.
   // FIXME: allocate values lazily, instead of just creating a fresh value.
-  BoolValue *BoolVal1 = getHasValue(Env, Env.getValue(*Loc1));
+  BoolValue *BoolVal1 = getHasValue(Env, Loc1);
   if (BoolVal1 == nullptr)
     BoolVal1 = &Env.makeAtomicBoolValue();
 
-  BoolValue *BoolVal2 = getHasValue(Env, Env.getValue(*Loc2));
+  BoolValue *BoolVal2 = getHasValue(Env, Loc2);
   if (BoolVal2 == nullptr)
     BoolVal2 = &Env.makeAtomicBoolValue();
 
@@ -712,20 +585,26 @@ void transferOptionalAndOptionalCmp(const clang::CXXOperatorCallExpr *CmpExpr,
   Environment &Env = State.Env;
   auto &A = Env.arena();
   auto *CmpValue = &forceBoolValue(Env, *CmpExpr);
-  if (auto *LHasVal = getHasValue(Env, Env.getValue(*CmpExpr->getArg(0))))
-    if (auto *RHasVal = getHasValue(Env, Env.getValue(*CmpExpr->getArg(1)))) {
+  auto *Arg0Loc = cast_or_null<RecordStorageLocation>(
+      Env.getStorageLocation(*CmpExpr->getArg(0)));
+  if (auto *LHasVal = getHasValue(Env, Arg0Loc)) {
+    auto *Arg1Loc = cast_or_null<RecordStorageLocation>(
+        Env.getStorageLocation(*CmpExpr->getArg(1)));
+    if (auto *RHasVal = getHasValue(Env, Arg1Loc)) {
       if (CmpExpr->getOperator() == clang::OO_ExclaimEqual)
         CmpValue = &A.makeNot(*CmpValue);
       Env.assume(evaluateEquality(A, *CmpValue, LHasVal->formula(),
                                   RHasVal->formula()));
     }
+  }
 }
 
 void transferOptionalAndValueCmp(const clang::CXXOperatorCallExpr *CmpExpr,
                                  const clang::Expr *E, Environment &Env) {
   auto &A = Env.arena();
   auto *CmpValue = &forceBoolValue(Env, *CmpExpr);
-  if (auto *HasVal = getHasValue(Env, Env.getValue(*E))) {
+  auto *Loc = cast_or_null<RecordStorageLocation>(Env.getStorageLocation(*E));
+  if (auto *HasVal = getHasValue(Env, Loc)) {
     if (CmpExpr->getOperator() == clang::OO_ExclaimEqual)
       CmpValue = &A.makeNot(*CmpValue);
     Env.assume(
@@ -733,6 +612,19 @@ void transferOptionalAndValueCmp(const clang::CXXOperatorCallExpr *CmpExpr,
   }
 }
 
+void transferOptionalAndNulloptCmp(const clang::CXXOperatorCallExpr *CmpExpr,
+                                   const clang::Expr *E, Environment &Env) {
+  auto &A = Env.arena();
+  auto *CmpValue = &forceBoolValue(Env, *CmpExpr);
+  auto *Loc = cast_or_null<RecordStorageLocation>(Env.getStorageLocation(*E));
+  if (auto *HasVal = getHasValue(Env, Loc)) {
+    if (CmpExpr->getOperator() == clang::OO_ExclaimEqual)
+      CmpValue = &A.makeNot(*CmpValue);
+    Env.assume(evaluateEquality(A, *CmpValue, HasVal->formula(),
+                                A.makeLiteral(false)));
+  }
+}
+
 std::optional<StatementMatcher>
 ignorableOptional(const UncheckedOptionalAccessModelOptions &Options) {
   if (Options.IgnoreSmartPointerDereference) {
@@ -762,12 +654,6 @@ auto buildTransferMatchSwitch() {
   // lot of duplicated work (e.g. string comparisons), consider providing APIs
   // that avoid it through memoization.
   return CFGMatchSwitchBuilder<LatticeTransferState>()
-      // Attach a symbolic "has_value" state to optional values that we see for
-      // the first time.
-      .CaseOfCFGStmt<Expr>(
-          expr(anyOf(declRefExpr(), memberExpr()), hasOptionalType()),
-          initializeOptionalReference)
-
       // make_optional
       .CaseOfCFGStmt<CallExpr>(isMakeOptionalCall(), transferMakeOptionalCall)
 
@@ -779,14 +665,6 @@ auto buildTransferMatchSwitch() {
             constructOptionalValue(*E, State.Env,
                                    State.Env.getBoolLiteralValue(true));
           })
-      // nullopt_t::nullopt_t
-      .CaseOfCFGStmt<CXXConstructExpr>(
-          isNulloptConstructor(),
-          [](const CXXConstructExpr *E, const MatchFinder::MatchResult &,
-             LatticeTransferState &State) {
-            constructOptionalValue(*E, State.Env,
-                                   State.Env.getBoolLiteralValue(false));
-          })
       // optional::optional(nullopt_t)
       .CaseOfCFGStmt<CXXConstructExpr>(
           isOptionalNulloptConstructor(),
@@ -887,18 +765,32 @@ auto buildTransferMatchSwitch() {
 
       // Comparisons (==, !=):
       .CaseOfCFGStmt<CXXOperatorCallExpr>(
-          isComparisonOperatorCall(hasAnyOptionalType(), hasAnyOptionalType()),
+          isComparisonOperatorCall(hasOptionalType(), hasOptionalType()),
           transferOptionalAndOptionalCmp)
       .CaseOfCFGStmt<CXXOperatorCallExpr>(
-          isComparisonOperatorCall(hasOptionalType(),
-                                   unless(hasAnyOptionalType())),
+          isComparisonOperatorCall(hasOptionalType(), hasNulloptType()),
+          [](const clang::CXXOperatorCallExpr *Cmp,
+             const MatchFinder::MatchResult &, LatticeTransferState &State) {
+            transferOptionalAndNulloptCmp(Cmp, Cmp->getArg(0), State.Env);
+          })
+      .CaseOfCFGStmt<CXXOperatorCallExpr>(
+          isComparisonOperatorCall(hasNulloptType(), hasOptionalType()),
+          [](const clang::CXXOperatorCallExpr *Cmp,
+             const MatchFinder::MatchResult &, LatticeTransferState &State) {
+            transferOptionalAndNulloptCmp(Cmp, Cmp->getArg(1), State.Env);
+          })
+      .CaseOfCFGStmt<CXXOperatorCallExpr>(
+          isComparisonOperatorCall(
+              hasOptionalType(),
+              unless(anyOf(hasOptionalType(), hasNulloptType()))),
           [](const clang::CXXOperatorCallExpr *Cmp,
              const MatchFinder::MatchResult &, LatticeTransferState &State) {
             transferOptionalAndValueCmp(Cmp, Cmp->getArg(0), State.Env);
           })
       .CaseOfCFGStmt<CXXOperatorCallExpr>(
-          isComparisonOperatorCall(unless(hasAnyOptionalType()),
-                                   hasOptionalType()),
+          isComparisonOperatorCall(
+              unless(anyOf(hasOptionalType(), hasNulloptType())),
+              hasOptionalType()),
           [](const clang::CXXOperatorCallExpr *Cmp,
              const MatchFinder::MatchResult &, LatticeTransferState &State) {
             transferOptionalAndValueCmp(Cmp, Cmp->getArg(1), State.Env);
@@ -913,8 +805,9 @@ auto buildTransferMatchSwitch() {
 
 llvm::SmallVector<SourceLocation> diagnoseUnwrapCall(const Expr *ObjectExpr,
                                                      const Environment &Env) {
-  if (auto *OptionalVal = getValueBehindPossiblePointer(*ObjectExpr, Env)) {
-    auto *Prop = OptionalVal->getProperty("has_value");
+  if (auto *OptionalLoc = cast_or_null<RecordStorageLocation>(
+          getLocBehindPossiblePointer(*ObjectExpr, Env))) {
+    auto *Prop = Env.getValue(locForHasValue(*OptionalLoc));
     if (auto *HasValueVal = cast_or_null<BoolValue>(Prop)) {
       if (Env.proves(HasValueVal->formula()))
         return {};
@@ -960,9 +853,24 @@ UncheckedOptionalAccessModel::optionalClassDecl() {
   return optionalClass();
 }
 
-UncheckedOptionalAccessModel::UncheckedOptionalAccessModel(ASTContext &Ctx)
+static QualType valueTypeFromOptionalType(QualType OptionalTy) {
+  auto *CTSD =
+      cast<ClassTemplateSpecializationDecl>(OptionalTy->getAsCXXRecordDecl());
+  return CTSD->getTemplateArgs()[0].getAsType();
+}
+
+UncheckedOptionalAccessModel::UncheckedOptionalAccessModel(ASTContext &Ctx,
+                                                           Environment &Env)
     : DataflowAnalysis<UncheckedOptionalAccessModel, NoopLattice>(Ctx),
-      TransferMatchSwitch(buildTransferMatchSwitch()) {}
+      TransferMatchSwitch(buildTransferMatchSwitch()) {
+  Env.getDataflowAnalysisContext().setSyntheticFieldCallback(
+      [&Ctx](QualType Ty) -> llvm::StringMap<QualType> {
+        if (!isOptionalType(Ty))
+          return {};
+        return {{"value", valueTypeFromOptionalType(Ty)},
+                {"has_value", Ctx.BoolTy}};
+      });
+}
 
 void UncheckedOptionalAccessModel::transfer(const CFGElement &Elt,
                                             NoopLattice &L, Environment &Env) {
@@ -970,76 +878,6 @@ void UncheckedOptionalAccessModel::transfer(const CFGElement &Elt,
   TransferMatchSwitch(Elt, getASTContext(), State);
 }
 
-ComparisonResult UncheckedOptionalAccessModel::compare(
-    QualType Type, const Value &Val1, const Environment &Env1,
-    const Value &Val2, const Environment &Env2) {
-  if (!isOptionalType(Type))
-    return ComparisonResult::Unknown;
-  bool MustNonEmpty1 = isNonEmptyOptional(Val1, Env1);
-  bool MustNonEmpty2 = isNonEmptyOptional(Val2, Env2);
-  if (MustNonEmpty1 && MustNonEmpty2)
-    return ComparisonResult::Same;
-  // If exactly one is true, then they're different, no reason to check whether
-  // they're definitely empty.
-  if (MustNonEmpty1 || MustNonEmpty2)
-    return ComparisonResult::Different;
-  // Check if they're both definitely empty.
-  return (isEmptyOptional(Val1, Env1) && isEmptyOptional(Val2, Env2))
-             ? ComparisonResult::Same
-             : ComparisonResult::Different;
-}
-
-bool UncheckedOptionalAccessModel::merge(QualType Type, const Value &Val1,
-                                         const Environment &Env1,
-                                         const Value &Val2,
-                                         const Environment &Env2,
-                                         Value &MergedVal,
-                                         Environment &MergedEnv) {
-  if (!isOptionalType(Type))
-    return true;
-  // FIXME: uses same approach as join for `BoolValues`. Requires non-const
-  // values, though, so will require updating the interface.
-  auto &HasValueVal = MergedEnv.makeAtomicBoolValue();
-  bool MustNonEmpty1 = isNonEmptyOptional(Val1, Env1);
-  bool MustNonEmpty2 = isNonEmptyOptional(Val2, Env2);
-  if (MustNonEmpty1 && MustNonEmpty2)
-    MergedEnv.assume(HasValueVal.formula());
-  else if (
-      // Only make the costly calls to `isEmptyOptional` if we got "unknown"
-      // (false) for both calls to `isNonEmptyOptional`.
-      !MustNonEmpty1 && !MustNonEmpty2 && isEmptyOptional(Val1, Env1) &&
-      isEmptyOptional(Val2, Env2))
-    MergedEnv.assume(MergedEnv.arena().makeNot(HasValueVal.formula()));
-  setHasValue(MergedVal, HasValueVal);
-  return true;
-}
-
-Value *UncheckedOptionalAccessModel::widen(QualType Type, Value &Prev,
-                                           const Environment &PrevEnv,
-                                           Value &Current,
-                                           Environment &CurrentEnv) {
-  switch (compare(Type, Prev, PrevEnv, Current, CurrentEnv)) {
-  case ComparisonResult::Same:
-    return &Prev;
-  case ComparisonResult::Different:
-    if (auto *PrevHasVal =
-            cast_or_null<BoolValue>(Prev.getProperty("has_value"))) {
-      if (isa<TopBoolValue>(PrevHasVal))
-        return &Prev;
-    }
-    if (auto *CurrentHasVal =
-            cast_or_null<BoolValue>(Current.getProperty("has_value"))) {
-      if (isa<TopBoolValue>(CurrentHasVal))
-        return &Current;
-    }
-    return &createOptionalValue(cast<RecordValue>(Current).getLoc(),
-                                CurrentEnv.makeTopBoolValue(), CurrentEnv);
-  case ComparisonResult::Unknown:
-    return nullptr;
-  }
-  llvm_unreachable("all cases covered in switch");
-}
-
 UncheckedOptionalAccessDiagnoser::UncheckedOptionalAccessDiagnoser(
     UncheckedOptionalAccessModelOptions Options)
     : DiagnoseMatchSwitch(buildDiagnoseMatchSwitch(Options)) {}
diff --git a/clang/lib/Analysis/FlowSensitive/RecordOps.cpp b/clang/lib/Analysis/FlowSensitive/RecordOps.cpp
index 38638f8..caaf443 100644
--- a/clang/lib/Analysis/FlowSensitive/RecordOps.cpp
+++ b/clang/lib/Analysis/FlowSensitive/RecordOps.cpp
@@ -54,6 +54,18 @@ void clang::dataflow::copyRecord(RecordStorageLocation &Src,
     }
   }
 
+  for (const auto &[Name, SynthFieldLoc] : Src.synthetic_fields()) {
+    if (SynthFieldLoc->getType()->isRecordType()) {
+      copyRecord(*cast<RecordStorageLocation>(SynthFieldLoc),
+                 cast<RecordStorageLocation>(Dst.getSyntheticField(Name)), Env);
+    } else {
+      if (Value *Val = Env.getValue(*SynthFieldLoc))
+        Env.setValue(Dst.getSyntheticField(Name), *Val);
+      else
+        Env.clearValue(Dst.getSyntheticField(Name));
+    }
+  }
+
   RecordValue *SrcVal = cast_or_null<RecordValue>(Env.getValue(Src));
   RecordValue *DstVal = cast_or_null<RecordValue>(Env.getValue(Dst));
 
@@ -101,6 +113,18 @@ bool clang::dataflow::recordsEqual(const RecordStorageLocation &Loc1,
     }
   }
 
+  for (const auto &[Name, SynthFieldLoc1] : Loc1.synthetic_fields()) {
+    if (SynthFieldLoc1->getType()->isRecordType()) {
+      if (!recordsEqual(
+              *cast<RecordStorageLocation>(SynthFieldLoc1), Env1,
+              cast<RecordStorageLocation>(Loc2.getSyntheticField(Name)), Env2))
+        return false;
+    } else if (Env1.getValue(*SynthFieldLoc1) !=
+               Env2.getValue(Loc2.getSyntheticField(Name))) {
+      return false;
+    }
+  }
+
   llvm::StringMap<Value *> Props1, Props2;
 
   if (RecordValue *Val1 = cast_or_null<RecordValue>(Env1.getValue(Loc1)))
diff --git a/clang/lib/Analysis/FlowSensitive/Transfer.cpp b/clang/lib/Analysis/FlowSensitive/Transfer.cpp
index 4343af79..bbf5f12 100644
--- a/clang/lib/Analysis/FlowSensitive/Transfer.cpp
+++ b/clang/lib/Analysis/FlowSensitive/Transfer.cpp
@@ -703,20 +703,18 @@ public:
     // `InitListExpr`, all fields in the class, including those from base
     // classes, are included in the set of modeled fields. The code above
     // should therefore populate exactly the modeled fields.
-    assert([&]() {
-      auto ModeledFields =
-          Env.getDataflowAnalysisContext().getModeledFields(Type);
-      if (ModeledFields.size() != FieldLocs.size())
-        return false;
-      for ([[maybe_unused]] auto [Field, Loc] : FieldLocs)
-        if (!ModeledFields.contains(cast_or_null<FieldDecl>(Field)))
-          return false;
-      return true;
-    }());
-
-    auto &Loc =
-        Env.getDataflowAnalysisContext().arena().create<RecordStorageLocation>(
-            Type, std::move(FieldLocs));
+    assert(containsSameFields(
+        Env.getDataflowAnalysisContext().getModeledFields(Type), FieldLocs));
+
+    RecordStorageLocation::SyntheticFieldMap SyntheticFieldLocs;
+    for (const auto &Entry :
+         Env.getDataflowAnalysisContext().getSyntheticFields(Type)) {
+      SyntheticFieldLocs.insert(
+          {Entry.getKey(), &Env.createObject(Entry.getValue())});
+    }
+
+    auto &Loc = Env.getDataflowAnalysisContext().createRecordStorageLocation(
+        Type, std::move(FieldLocs), std::move(SyntheticFieldLocs));
     RecordValue &RecordVal = Env.create<RecordValue>(Loc);
 
     Env.setValue(Loc, RecordVal);
diff --git a/clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp b/clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp
index ade8c84..8c93602 100644
--- a/clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp
+++ b/clang/lib/Analysis/FlowSensitive/TypeErasedDataflowAnalysis.cpp
@@ -501,6 +501,14 @@ runTypeErasedDataflowAnalysis(
         PostVisitCFG) {
   PrettyStackTraceAnalysis CrashInfo(CFCtx, "runTypeErasedDataflowAnalysis");
 
+  std::optional<Environment> MaybeStartingEnv;
+  if (InitEnv.callStackSize() == 1) {
+    MaybeStartingEnv = InitEnv.fork();
+    MaybeStartingEnv->initialize();
+  }
+  const Environment &StartingEnv =
+      MaybeStartingEnv ? *MaybeStartingEnv : InitEnv;
+
   const clang::CFG &CFG = CFCtx.getCFG();
   PostOrderCFGView POV(&CFG);
   ForwardDataflowWorklist Worklist(CFG, &POV);
@@ -511,10 +519,10 @@ runTypeErasedDataflowAnalysis(
   // The entry basic block doesn't contain statements so it can be skipped.
   const CFGBlock &Entry = CFG.getEntry();
   BlockStates[Entry.getBlockID()] = {Analysis.typeErasedInitialElement(),
-                                     InitEnv.fork()};
+                                     StartingEnv.fork()};
   Worklist.enqueueSuccessors(&Entry);
 
-  AnalysisContext AC(CFCtx, Analysis, InitEnv, BlockStates);
+  AnalysisContext AC(CFCtx, Analysis, StartingEnv, BlockStates);
 
   // Bugs in lattices and transfer functions can prevent the analysis from
   // converging. To limit the damage (infinite loops) that these bugs can cause,