[clang][dataflow] Expose fields, globals, and functions referenced.

[bazuzi]

Exposes the collection functionality, but does not alter it beyond using a return value instead of output parameters. Also relocates underlying and related functions and a class from DataflowEnvironment's files to DataflowAnalysisContext's files, as no Environment is needed.

[llvmbot]

@llvm/pr-subscribers-clang-analysis

@llvm/pr-subscribers-clang

Author: Samira Bazuzi (bazuzi)

Changes

Exposes the collection functionality, but does not alter it beyond using a return value instead of output parameters. Also relocates underlying and related functions and a class from DataflowEnvironment's files to DataflowAnalysisContext's files, as no Environment is needed.

---

Patch is 21.33 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/88534.diff

5 Files Affected:

• (modified) clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h (+46)
• (modified) clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h (-36)
• (modified) clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp (+174)
• (modified) clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp (+4-172)
• (modified) clang/lib/Analysis/FlowSensitive/Transfer.cpp (+1)

diff --git a/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h b/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
index 909a91059438ca..a34e5f603eb396 100644
--- a/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
+++ b/clang/include/clang/Analysis/FlowSensitive/DataflowAnalysisContext.h
@@ -62,6 +62,52 @@ FieldSet getObjectFields(QualType Type);
 bool containsSameFields(const FieldSet &Fields,
                         const RecordStorageLocation::FieldToLoc &FieldLocs);
 
+/// Returns the fields of a `RecordDecl` that are initialized by an
+/// `InitListExpr`, in the order in which they appear in
+/// `InitListExpr::inits()`.
+/// `Init->getType()` must be a record type.
+std::vector<const FieldDecl *>
+getFieldsForInitListExpr(const InitListExpr *InitList);
+
+/// Helper class for initialization of a record with an `InitListExpr`.
+/// `InitListExpr::inits()` contains the initializers for both the base classes
+/// and the fields of the record; this helper class separates these out into two
+/// different lists. In addition, it deals with special cases associated with
+/// unions.
+class RecordInitListHelper {
+public:
+  // `InitList` must have record type.
+  RecordInitListHelper(const InitListExpr *InitList);
+
+  // Base classes with their associated initializer expressions.
+  ArrayRef<std::pair<const CXXBaseSpecifier *, Expr *>> base_inits() const {
+    return BaseInits;
+  }
+
+  // Fields with their associated initializer expressions.
+  ArrayRef<std::pair<const FieldDecl *, Expr *>> field_inits() const {
+    return FieldInits;
+  }
+
+private:
+  SmallVector<std::pair<const CXXBaseSpecifier *, Expr *>> BaseInits;
+  SmallVector<std::pair<const FieldDecl *, Expr *>> FieldInits;
+
+  // We potentially synthesize an `ImplicitValueInitExpr` for unions. It's a
+  // member variable because we store a pointer to it in `FieldInits`.
+  std::optional<ImplicitValueInitExpr> ImplicitValueInitForUnion;
+};
+
+struct FieldsGlobalsAndFuncs {
+  FieldSet Fields;
+  // Globals includes all variables with global storage, notably including
+  // static data members and static variables declared within a function.
+  llvm::DenseSet<const VarDecl *> Globals;
+  llvm::DenseSet<const FunctionDecl *> Funcs;
+};
+
+FieldsGlobalsAndFuncs getFieldsGlobalsAndFuncs(const FunctionDecl &FD);
+
 struct ContextSensitiveOptions {
   /// The maximum depth to analyze. A value of zero is equivalent to disabling
   /// context-sensitive analysis entirely.
diff --git a/clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h b/clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h
index 706664d7db1c25..4277792219c0af 100644
--- a/clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h
+++ b/clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h
@@ -775,42 +775,6 @@ RecordStorageLocation *getImplicitObjectLocation(const CXXMemberCallExpr &MCE,
 RecordStorageLocation *getBaseObjectLocation(const MemberExpr &ME,
                                              const Environment &Env);
 
-/// Returns the fields of a `RecordDecl` that are initialized by an
-/// `InitListExpr`, in the order in which they appear in
-/// `InitListExpr::inits()`.
-/// `Init->getType()` must be a record type.
-std::vector<const FieldDecl *>
-getFieldsForInitListExpr(const InitListExpr *InitList);
-
-/// Helper class for initialization of a record with an `InitListExpr`.
-/// `InitListExpr::inits()` contains the initializers for both the base classes
-/// and the fields of the record; this helper class separates these out into two
-/// different lists. In addition, it deals with special cases associated with
-/// unions.
-class RecordInitListHelper {
-public:
-  // `InitList` must have record type.
-  RecordInitListHelper(const InitListExpr *InitList);
-
-  // Base classes with their associated initializer expressions.
-  ArrayRef<std::pair<const CXXBaseSpecifier *, Expr *>> base_inits() const {
-    return BaseInits;
-  }
-
-  // Fields with their associated initializer expressions.
-  ArrayRef<std::pair<const FieldDecl *, Expr *>> field_inits() const {
-    return FieldInits;
-  }
-
-private:
-  SmallVector<std::pair<const CXXBaseSpecifier *, Expr *>> BaseInits;
-  SmallVector<std::pair<const FieldDecl *, Expr *>> FieldInits;
-
-  // We potentially synthesize an `ImplicitValueInitExpr` for unions. It's a
-  // member variable because we store a pointer to it in `FieldInits`.
-  std::optional<ImplicitValueInitExpr> ImplicitValueInitForUnion;
-};
-
 /// Associates a new `RecordValue` with `Loc` and returns the new value.
 RecordValue &refreshRecordValue(RecordStorageLocation &Loc, Environment &Env);
 
diff --git a/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp b/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
index d520539dd25355..74b1299f014c66 100644
--- a/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
+++ b/clang/lib/Analysis/FlowSensitive/DataflowAnalysisContext.cpp
@@ -55,6 +55,180 @@ FieldSet DataflowAnalysisContext::getModeledFields(QualType Type) {
   return llvm::set_intersection(getObjectFields(Type), ModeledFields);
 }
 
+std::vector<const FieldDecl *>
+getFieldsForInitListExpr(const InitListExpr *InitList) {
+  const RecordDecl *RD = InitList->getType()->getAsRecordDecl();
+  assert(RD != nullptr);
+
+  std::vector<const FieldDecl *> Fields;
+
+  if (InitList->getType()->isUnionType()) {
+    Fields.push_back(InitList->getInitializedFieldInUnion());
+    return Fields;
+  }
+
+  // Unnamed bitfields are only used for padding and do not appear in
+  // `InitListExpr`'s inits. However, those fields do appear in `RecordDecl`'s
+  // field list, and we thus need to remove them before mapping inits to
+  // fields to avoid mapping inits to the wrongs fields.
+  llvm::copy_if(
+      RD->fields(), std::back_inserter(Fields),
+      [](const FieldDecl *Field) { return !Field->isUnnamedBitfield(); });
+  return Fields;
+}
+
+RecordInitListHelper::RecordInitListHelper(const InitListExpr *InitList) {
+  auto *RD = InitList->getType()->getAsCXXRecordDecl();
+  assert(RD != nullptr);
+
+  std::vector<const FieldDecl *> Fields = getFieldsForInitListExpr(InitList);
+  ArrayRef<Expr *> Inits = InitList->inits();
+
+  // Unions initialized with an empty initializer list need special treatment.
+  // For structs/classes initialized with an empty initializer list, Clang
+  // puts `ImplicitValueInitExpr`s in `InitListExpr::inits()`, but for unions,
+  // it doesn't do this -- so we create an `ImplicitValueInitExpr` ourselves.
+  SmallVector<Expr *> InitsForUnion;
+  if (InitList->getType()->isUnionType() && Inits.empty()) {
+    assert(Fields.size() == 1);
+    ImplicitValueInitForUnion.emplace(Fields.front()->getType());
+    InitsForUnion.push_back(&*ImplicitValueInitForUnion);
+    Inits = InitsForUnion;
+  }
+
+  size_t InitIdx = 0;
+
+  assert(Fields.size() + RD->getNumBases() == Inits.size());
+  for (const CXXBaseSpecifier &Base : RD->bases()) {
+    assert(InitIdx < Inits.size());
+    Expr *Init = Inits[InitIdx++];
+    BaseInits.emplace_back(&Base, Init);
+  }
+
+  assert(Fields.size() == Inits.size() - InitIdx);
+  for (const FieldDecl *Field : Fields) {
+    assert(InitIdx < Inits.size());
+    Expr *Init = Inits[InitIdx++];
+    FieldInits.emplace_back(Field, Init);
+  }
+}
+
+static void insertIfGlobal(const Decl &D,
+                           llvm::DenseSet<const VarDecl *> &Vars) {
+  if (auto *V = dyn_cast<VarDecl>(&D))
+    if (V->hasGlobalStorage())
+      Vars.insert(V);
+}
+
+static void insertIfFunction(const Decl &D,
+                             llvm::DenseSet<const FunctionDecl *> &Funcs) {
+  if (auto *FD = dyn_cast<FunctionDecl>(&D))
+    Funcs.insert(FD);
+}
+
+static MemberExpr *getMemberForAccessor(const CXXMemberCallExpr &C) {
+  // Use getCalleeDecl instead of getMethodDecl in order to handle
+  // pointer-to-member calls.
+  const auto *MethodDecl = dyn_cast_or_null<CXXMethodDecl>(C.getCalleeDecl());
+  if (!MethodDecl)
+    return nullptr;
+  auto *Body = dyn_cast_or_null<CompoundStmt>(MethodDecl->getBody());
+  if (!Body || Body->size() != 1)
+    return nullptr;
+  if (auto *RS = dyn_cast<ReturnStmt>(*Body->body_begin()))
+    if (auto *Return = RS->getRetValue())
+      return dyn_cast<MemberExpr>(Return->IgnoreParenImpCasts());
+  return nullptr;
+}
+
+static void
+getFieldsGlobalsAndFuncs(const Decl &D, FieldSet &Fields,
+                         llvm::DenseSet<const VarDecl *> &Vars,
+                         llvm::DenseSet<const FunctionDecl *> &Funcs) {
+  insertIfGlobal(D, Vars);
+  insertIfFunction(D, Funcs);
+  if (const auto *Decomp = dyn_cast<DecompositionDecl>(&D))
+    for (const auto *B : Decomp->bindings())
+      if (auto *ME = dyn_cast_or_null<MemberExpr>(B->getBinding()))
+        // FIXME: should we be using `E->getFoundDecl()`?
+        if (const auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl()))
+          Fields.insert(FD);
+}
+
+/// Traverses `S` and inserts into `Fields`, `Vars` and `Funcs` any fields,
+/// global variables and functions that are declared in or referenced from
+/// sub-statements.
+static void
+getFieldsGlobalsAndFuncs(const Stmt &S, FieldSet &Fields,
+                         llvm::DenseSet<const VarDecl *> &Vars,
+                         llvm::DenseSet<const FunctionDecl *> &Funcs) {
+  for (auto *Child : S.children())
+    if (Child != nullptr)
+      getFieldsGlobalsAndFuncs(*Child, Fields, Vars, Funcs);
+  if (const auto *DefaultArg = dyn_cast<CXXDefaultArgExpr>(&S))
+    getFieldsGlobalsAndFuncs(*DefaultArg->getExpr(), Fields, Vars, Funcs);
+  if (const auto *DefaultInit = dyn_cast<CXXDefaultInitExpr>(&S))
+    getFieldsGlobalsAndFuncs(*DefaultInit->getExpr(), Fields, Vars, Funcs);
+
+  if (auto *DS = dyn_cast<DeclStmt>(&S)) {
+    if (DS->isSingleDecl())
+      getFieldsGlobalsAndFuncs(*DS->getSingleDecl(), Fields, Vars, Funcs);
+    else
+      for (auto *D : DS->getDeclGroup())
+        getFieldsGlobalsAndFuncs(*D, Fields, Vars, Funcs);
+  } else if (auto *E = dyn_cast<DeclRefExpr>(&S)) {
+    insertIfGlobal(*E->getDecl(), Vars);
+    insertIfFunction(*E->getDecl(), Funcs);
+  } else if (const auto *C = dyn_cast<CXXMemberCallExpr>(&S)) {
+    // If this is a method that returns a member variable but does nothing else,
+    // model the field of the return value.
+    if (MemberExpr *E = getMemberForAccessor(*C))
+      if (const auto *FD = dyn_cast<FieldDecl>(E->getMemberDecl()))
+        Fields.insert(FD);
+  } else if (auto *E = dyn_cast<MemberExpr>(&S)) {
+    // FIXME: should we be using `E->getFoundDecl()`?
+    const ValueDecl *VD = E->getMemberDecl();
+    insertIfGlobal(*VD, Vars);
+    insertIfFunction(*VD, Funcs);
+    if (const auto *FD = dyn_cast<FieldDecl>(VD))
+      Fields.insert(FD);
+  } else if (auto *InitList = dyn_cast<InitListExpr>(&S)) {
+    if (InitList->getType()->isRecordType())
+      for (const auto *FD : getFieldsForInitListExpr(InitList))
+        Fields.insert(FD);
+  }
+}
+
+/// Collects and returns fields, global variables and functions that are
+/// declared in or referenced from `FD`.
+FieldsGlobalsAndFuncs getFieldsGlobalsAndFuncs(const FunctionDecl &FD) {
+  FieldsGlobalsAndFuncs Result;
+  // Look for global variable and field references in the
+  // constructor-initializers.
+  if (const auto *CtorDecl = dyn_cast<CXXConstructorDecl>(&FD)) {
+    for (const auto *Init : CtorDecl->inits()) {
+      if (Init->isMemberInitializer()) {
+        Result.Fields.insert(Init->getMember());
+      } else if (Init->isIndirectMemberInitializer()) {
+        for (const auto *I : Init->getIndirectMember()->chain())
+          Result.Fields.insert(cast<FieldDecl>(I));
+      }
+      const Expr *E = Init->getInit();
+      assert(E != nullptr);
+      getFieldsGlobalsAndFuncs(*E, Result.Fields, Result.Globals, Result.Funcs);
+    }
+    // Add all fields mentioned in default member initializers.
+    for (const FieldDecl *F : CtorDecl->getParent()->fields())
+      if (const auto *I = F->getInClassInitializer())
+        getFieldsGlobalsAndFuncs(*I, Result.Fields, Result.Globals,
+                                 Result.Funcs);
+  }
+  getFieldsGlobalsAndFuncs(*FD.getBody(), Result.Fields, Result.Globals,
+                           Result.Funcs);
+
+  return Result;
+}
+
 void DataflowAnalysisContext::addModeledFields(const FieldSet &Fields) {
   ModeledFields.set_union(Fields);
 }
diff --git a/clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp b/clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp
index bea15ce9bd24d1..6dae25441968de 100644
--- a/clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp
+++ b/clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp
@@ -304,93 +304,6 @@ widenKeyToValueMap(const llvm::MapVector<Key, Value *> &CurMap,
   return WidenedMap;
 }
 
-/// Initializes a global storage value.
-static void insertIfGlobal(const Decl &D,
-                           llvm::DenseSet<const VarDecl *> &Vars) {
-  if (auto *V = dyn_cast<VarDecl>(&D))
-    if (V->hasGlobalStorage())
-      Vars.insert(V);
-}
-
-static void insertIfFunction(const Decl &D,
-                             llvm::DenseSet<const FunctionDecl *> &Funcs) {
-  if (auto *FD = dyn_cast<FunctionDecl>(&D))
-    Funcs.insert(FD);
-}
-
-static MemberExpr *getMemberForAccessor(const CXXMemberCallExpr &C) {
-  // Use getCalleeDecl instead of getMethodDecl in order to handle
-  // pointer-to-member calls.
-  const auto *MethodDecl = dyn_cast_or_null<CXXMethodDecl>(C.getCalleeDecl());
-  if (!MethodDecl)
-    return nullptr;
-  auto *Body = dyn_cast_or_null<CompoundStmt>(MethodDecl->getBody());
-  if (!Body || Body->size() != 1)
-    return nullptr;
-  if (auto *RS = dyn_cast<ReturnStmt>(*Body->body_begin()))
-    if (auto *Return = RS->getRetValue())
-      return dyn_cast<MemberExpr>(Return->IgnoreParenImpCasts());
-  return nullptr;
-}
-
-static void
-getFieldsGlobalsAndFuncs(const Decl &D, FieldSet &Fields,
-                         llvm::DenseSet<const VarDecl *> &Vars,
-                         llvm::DenseSet<const FunctionDecl *> &Funcs) {
-  insertIfGlobal(D, Vars);
-  insertIfFunction(D, Funcs);
-  if (const auto *Decomp = dyn_cast<DecompositionDecl>(&D))
-    for (const auto *B : Decomp->bindings())
-      if (auto *ME = dyn_cast_or_null<MemberExpr>(B->getBinding()))
-        // FIXME: should we be using `E->getFoundDecl()`?
-        if (const auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl()))
-          Fields.insert(FD);
-}
-
-/// Traverses `S` and inserts into `Fields`, `Vars` and `Funcs` any fields,
-/// global variables and functions that are declared in or referenced from
-/// sub-statements.
-static void
-getFieldsGlobalsAndFuncs(const Stmt &S, FieldSet &Fields,
-                         llvm::DenseSet<const VarDecl *> &Vars,
-                         llvm::DenseSet<const FunctionDecl *> &Funcs) {
-  for (auto *Child : S.children())
-    if (Child != nullptr)
-      getFieldsGlobalsAndFuncs(*Child, Fields, Vars, Funcs);
-  if (const auto *DefaultArg = dyn_cast<CXXDefaultArgExpr>(&S))
-    getFieldsGlobalsAndFuncs(*DefaultArg->getExpr(), Fields, Vars, Funcs);
-  if (const auto *DefaultInit = dyn_cast<CXXDefaultInitExpr>(&S))
-    getFieldsGlobalsAndFuncs(*DefaultInit->getExpr(), Fields, Vars, Funcs);
-
-  if (auto *DS = dyn_cast<DeclStmt>(&S)) {
-    if (DS->isSingleDecl())
-      getFieldsGlobalsAndFuncs(*DS->getSingleDecl(), Fields, Vars, Funcs);
-    else
-      for (auto *D : DS->getDeclGroup())
-        getFieldsGlobalsAndFuncs(*D, Fields, Vars, Funcs);
-  } else if (auto *E = dyn_cast<DeclRefExpr>(&S)) {
-    insertIfGlobal(*E->getDecl(), Vars);
-    insertIfFunction(*E->getDecl(), Funcs);
-  } else if (const auto *C = dyn_cast<CXXMemberCallExpr>(&S)) {
-    // If this is a method that returns a member variable but does nothing else,
-    // model the field of the return value.
-    if (MemberExpr *E = getMemberForAccessor(*C))
-      if (const auto *FD = dyn_cast<FieldDecl>(E->getMemberDecl()))
-        Fields.insert(FD);
-  } else if (auto *E = dyn_cast<MemberExpr>(&S)) {
-    // FIXME: should we be using `E->getFoundDecl()`?
-    const ValueDecl *VD = E->getMemberDecl();
-    insertIfGlobal(*VD, Vars);
-    insertIfFunction(*VD, Funcs);
-    if (const auto *FD = dyn_cast<FieldDecl>(VD))
-      Fields.insert(FD);
-  } else if (auto *InitList = dyn_cast<InitListExpr>(&S)) {
-    if (InitList->getType()->isRecordType())
-      for (const auto *FD : getFieldsForInitListExpr(InitList))
-        Fields.insert(FD);
-  }
-}
-
 namespace {
 
 // Visitor that builds a map from record prvalues to result objects.
@@ -648,36 +561,13 @@ void Environment::initialize() {
 void Environment::initFieldsGlobalsAndFuncs(const FunctionDecl *FuncDecl) {
   assert(FuncDecl->doesThisDeclarationHaveABody());
 
-  FieldSet Fields;
-  llvm::DenseSet<const VarDecl *> Vars;
-  llvm::DenseSet<const FunctionDecl *> Funcs;
-
-  // Look for global variable and field references in the
-  // constructor-initializers.
-  if (const auto *CtorDecl = dyn_cast<CXXConstructorDecl>(FuncDecl)) {
-    for (const auto *Init : CtorDecl->inits()) {
-      if (Init->isMemberInitializer()) {
-        Fields.insert(Init->getMember());
-      } else if (Init->isIndirectMemberInitializer()) {
-        for (const auto *I : Init->getIndirectMember()->chain())
-          Fields.insert(cast<FieldDecl>(I));
-      }
-      const Expr *E = Init->getInit();
-      assert(E != nullptr);
-      getFieldsGlobalsAndFuncs(*E, Fields, Vars, Funcs);
-    }
-    // Add all fields mentioned in default member initializers.
-    for (const FieldDecl *F : CtorDecl->getParent()->fields())
-      if (const auto *I = F->getInClassInitializer())
-          getFieldsGlobalsAndFuncs(*I, Fields, Vars, Funcs);
-  }
-  getFieldsGlobalsAndFuncs(*FuncDecl->getBody(), Fields, Vars, Funcs);
+  FieldsGlobalsAndFuncs FGF = getFieldsGlobalsAndFuncs(*FuncDecl);
 
   // These have to be added before the lines that follow to ensure that
   // `create*` work correctly for structs.
-  DACtx->addModeledFields(Fields);
+  DACtx->addModeledFields(FGF.Fields);
 
-  for (const VarDecl *D : Vars) {
+  for (const VarDecl *D : FGF.Globals) {
     if (getStorageLocation(*D) != nullptr)
       continue;
 
@@ -689,7 +579,7 @@ void Environment::initFieldsGlobalsAndFuncs(const FunctionDecl *FuncDecl) {
     setStorageLocation(*D, createObject(*D, nullptr));
   }
 
-  for (const FunctionDecl *FD : Funcs) {
+  for (const FunctionDecl *FD : FGF.Funcs) {
     if (getStorageLocation(*FD) != nullptr)
       continue;
     auto &Loc = createStorageLocation(*FD);
@@ -1349,64 +1239,6 @@ RecordStorageLocation *getBaseObjectLocation(const MemberExpr &ME,
   return Env.get<RecordStorageLocation>(*Base);
 }
 
-std::vector<const FieldDecl *>
-getFieldsForInitListExpr(const InitListExpr *InitList) {
-  const RecordDecl *RD = InitList->getType()->getAsRecordDecl();
-  assert(RD != nullptr);
-
-  std::vector<const FieldDecl *> Fields;
-
-  if (InitList->getType()->isUnionType()) {
-    Fields.push_back(InitList->getInitializedFieldInUnion());
-    return Fields;
-  }
-
-  // Unnamed bitfields are only used for padding and do not appear in
-  // `InitListExpr`'s inits. However, those fields do appear in `RecordDecl`'s
-  // field list, and we thus need to remove them before mapping inits to
-  // fields to avoid mapping inits to the wrongs fields.
-  llvm::copy_if(
-      RD->fields(), std::back_inserter(Fields),
-      [](const FieldDecl *Field) { return !Field->isUnnamedBitfield(); });
-  return Fields;
-}
-
-RecordInitListHelper::RecordInitListHelper(const InitListExpr *InitList) {
-  auto *RD = InitList->getType()->getAsCXXRecordDecl();
-  assert(RD != nullptr);
-
-  std::vector<const FieldDecl *> Fields = getFieldsForInitListExpr(InitList);
-  ArrayRef<Expr *> Inits = InitList->inits();
-
-  // Unions initialized with an empty initializer list need special treatment.
-  // For structs/classes initialized with an empty initializer list, Clang
-  // puts `ImplicitValueInitExpr`s in `InitListExpr::inits()`, but for unions,
-  // it doesn't do this -- so we create an `ImplicitValueInitExpr` ourselves.
-  SmallVector<Expr *> InitsForUnion;
-  if (InitList->getType()->isUnionType() && Inits.empty()) {
-    assert(Fields.size() == 1);
-    ImplicitValueInitForUnion.emplace(Fields.front()->getType());
-    Init...
[truncated]

[bazuzi]

@ymand Can you review and merge?

[ymand]

Thanks!

[ymand]

Comment Funcs? I'm actually not sure offhand what that's for. :)

[ymand]

Maybe prefix "Mentioned" or "Referenced" or "Used"?
Also, please add a brief comment. In context, it's role is obvious, but for cross-referencing tools, its often helpful to have comment when you're looking at a mention in another file.

[martinboehme]

My vote would be for Referenced, and I would also suggest replacing FieldsGlobalsAndFuncs (which is a name that IIRC has "accreted" over time). How about ReferencedDecls (and getReferencedDecls()), which reads better and will remain accurate if we add more types of declarations in the future?

[martinboehme]

DataflowAnalysisContext.h is starting to accumulate more and more functions that serve to extract various types of information from the AST; these aren't really related to the DataflowAnalysisContext, so I wonder if it's time to separate these out into their own header and implementation files?

(I realize that this process started well before this patch, but as the purpose of this patch is to move declarations to more suitable places, maybe we should use the opportunity to create a more suitable place instead of moving them to DataflowAnalysisContext.h, which isn't really a good home for them either.)

The common theme seems to be that these functions / classes all perform some operation on the AST, so maybe ASTOperations.h/.cpp? Not really a great name, but I think it's still a lot better than putting this all together with the DataflowAnalysisContext.

[martinboehme]

This appears to be used only in DataflowEnvironment.cpp -- would suggest simply making it a static function there (not exposed in any header).

(I believe it used to be that this was used more widely, but RecordInitListHelper made that unnecessary, and I didn't notice that when I introduced this class?)

[martinboehme]

My vote would be for Referenced, and I would also suggest replacing FieldsGlobalsAndFuncs (which is a name that IIRC has "accreted" over time). How about ReferencedDecls (and getReferencedDecls()), which reads better and will remain accurate if we add more types of declarations in the future?

[martinboehme]

Can you add a short comment for this function?

[bazuzi]

Sorry, screwed up my git push here. Going to close this to avoid hitting recent authors any more.