[clang][dataflow] Include fields initialized in an InitListExpr in getModeledFields().

Previously, we were including these fields only in the specific instance that was initialized by the `InitListExpr`, but not in other instances of the same type. This is inconsistent and error-prone.

Depends On D154952

Reviewed By: xazax.hun, gribozavr2

Differential Revision: https://reviews.llvm.org/D154961

Author: martinboehme

clang/include/clang/Analysis/FlowSensitive/DataflowEnvironment.h

@@ -644,6 +644,10 @@ getImplicitObjectLocation(const CXXMemberCallExpr &MCE, const Environment &Env);
 AggregateStorageLocation *getBaseObjectLocation(const MemberExpr &ME,
                                                 const Environment &Env);
 
+/// Returns the fields of `RD` that are initialized by an `InitListExpr`, in the
+/// order in which they appear in `InitListExpr::inits()`.
+std::vector<FieldDecl *> getFieldsForInitListExpr(const RecordDecl *RD);
+
 } // namespace dataflow
 } // namespace clang
 

clang/lib/Analysis/FlowSensitive/DataflowEnvironment.cpp

@@ -215,6 +215,10 @@ getFieldsGlobalsAndFuncs(const Stmt &S, FieldSet &Fields,
     insertIfFunction(*VD, Funcs);
     if (const auto *FD = dyn_cast<FieldDecl>(VD))
       Fields.insert(FD);
+  } else if (auto *InitList = dyn_cast<InitListExpr>(&S)) {
+    if (RecordDecl *RD = InitList->getType()->getAsRecordDecl())
+      for (const auto *FD : getFieldsForInitListExpr(RD))
+        Fields.insert(FD);
   }
 }
 
@@ -958,5 +962,17 @@ AggregateStorageLocation *getBaseObjectLocation(const MemberExpr &ME,
   return cast<AggregateStorageLocation>(Loc);
 }
 
+std::vector<FieldDecl *> getFieldsForInitListExpr(const RecordDecl *RD) {
+  // 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.
+  std::vector<FieldDecl *> Fields;
+  llvm::copy_if(
+      RD->fields(), std::back_inserter(Fields),
+      [](const FieldDecl *Field) { return !Field->isUnnamedBitfield(); });
+  return Fields;
+}
+
 } // namespace dataflow
 } // namespace clang

clang/lib/Analysis/FlowSensitive/Transfer.cpp

@@ -715,14 +715,8 @@ class TransferVisitor : public ConstStmtVisitor<TransferVisitor> {
     Env.setValue(Loc, *Val);
 
     if (Type->isStructureOrClassType()) {
-      // Unnamed bitfields are only used for padding and are not appearing 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.
-      std::vector<FieldDecl *> Fields;
-      llvm::copy_if(
-          Type->getAsRecordDecl()->fields(), std::back_inserter(Fields),
-          [](const FieldDecl *Field) { return !Field->isUnnamedBitfield(); });
+      std::vector<FieldDecl *> Fields =
+          getFieldsForInitListExpr(Type->getAsRecordDecl());
       for (auto It : llvm::zip(Fields, S->inits())) {
         const FieldDecl *Field = std::get<0>(It);
         assert(Field != nullptr);

clang/unittests/Analysis/FlowSensitive/TransferTest.cpp

@@ -2833,6 +2833,7 @@ TEST(TransferTest, AggregateInitialization) {
 
     void target(int BarArg, int FooArg, int QuxArg) {
       B Quux{BarArg, {FooArg}, QuxArg};
+      B OtherB;
       /*[[p]]*/
     }
   )";
@@ -2849,6 +2850,7 @@ TEST(TransferTest, AggregateInitialization) {
 
     void target(int BarArg, int FooArg, int QuxArg) {
       B Quux = {BarArg, FooArg, QuxArg};
+      B OtherB;
       /*[[p]]*/
     }
   )";
@@ -2898,6 +2900,14 @@ TEST(TransferTest, AggregateInitialization) {
           EXPECT_EQ(getFieldValue(QuuxVal, *BarDecl, Env), BarArgVal);
           EXPECT_EQ(getFieldValue(BazVal, *FooDecl, Env), FooArgVal);
           EXPECT_EQ(getFieldValue(QuuxVal, *QuxDecl, Env), QuxArgVal);
+
+          // Check that fields initialized in an initializer list are always
+          // modeled in other instances of the same type.
+          const auto &OtherBVal =
+              getValueForDecl<StructValue>(ASTCtx, Env, "OtherB");
+          EXPECT_THAT(OtherBVal.getChild(*BarDecl), NotNull());
+          EXPECT_THAT(OtherBVal.getChild(*BazDecl), NotNull());
+          EXPECT_THAT(OtherBVal.getChild(*QuxDecl), NotNull());
         });
   }
 }