Add TreatUnavailableAsInvalid for the verification-only mode in InitListChecker.

Given the following test case:
typedef struct {
  const char *name;
  id field;
} Test9;
extern void doSomething(Test9 arg);
void test9() {
  Test9 foo2 = {0, 0};
  doSomething(foo2);
}
With a release compiler, we don't emit any message and silently ignore the
variable "foo2". With an assert compiler, we get an assertion failure.

The root cause —————————————
Back in r140457 we gave InitListChecker a verification-only mode, and will use
CanUseDecl instead of DiagnoseUseOfDecl for verification-only mode.

These two functions handle unavailable issues differently:
In Sema::CanUseDecl, we say the decl is invalid when the Decl is unavailable and
the current context is available.

In Sema::DiagnoseUseOfDecl, we say the decl is usable by ignoring the return
code of DiagnoseAvailabilityOfDecl

So with an assert build, we will hit an assertion in diagnoseListInit
assert(DiagnoseInitList.HadError() &&
       "Inconsistent init list check result.");

The fix -------------------
If we follow what is implemented in CanUseDecl and treat Decls with
unavailable issues as invalid, the variable decl of “foo2” will be marked as
invalid. Since unavailable checking is processed in delayed diagnostics
(r197627), we will silently ignore the diagnostics when we find out that
the variable decl is invalid.

We add a flag "TreatUnavailableAsInvalid" for the verification-only mode.
For overload resolution, we want to say decls with unavailable issues are
invalid; but for everything else, we should say they are valid and
emit diagnostics. Depending on the value of the flag, CanUseDecl
can return different values for unavailable issues.

rdar://23557300
Differential Revision: http://reviews.llvm.org/D15314

llvm-svn: 263149

1 files changed, 57 insertions, 30 deletions

diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 3edabc64288..d30825360e1 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -238,6 +238,7 @@ class InitListChecker {
   Sema &SemaRef;
   bool hadError;
   bool VerifyOnly; // no diagnostics, no structure building
+  bool TreatUnavailableAsInvalid; // Used only in VerifyOnly mode.
   llvm::DenseMap<InitListExpr *, InitListExpr *> SyntacticToSemantic;
   InitListExpr *FullyStructuredList;
 
@@ -320,7 +321,8 @@ class InitListChecker {
   static ExprResult PerformEmptyInit(Sema &SemaRef,
                                      SourceLocation Loc,
                                      const InitializedEntity &Entity,
-                                     bool VerifyOnly);
+                                     bool VerifyOnly,
+                                     bool TreatUnavailableAsInvalid);
 
   // Explanation on the "FillWithNoInit" mode:
   //
@@ -360,7 +362,8 @@ class InitListChecker {
 
 public:
   InitListChecker(Sema &S, const InitializedEntity &Entity,
-                  InitListExpr *IL, QualType &T, bool VerifyOnly);
+                  InitListExpr *IL, QualType &T, bool VerifyOnly,
+                  bool TreatUnavailableAsInvalid);
   bool HadError() { return hadError; }
 
   // @brief Retrieves the fully-structured initializer list used for
@@ -373,7 +376,8 @@ public:
 ExprResult InitListChecker::PerformEmptyInit(Sema &SemaRef,
                                              SourceLocation Loc,
                                              const InitializedEntity &Entity,
-                                             bool VerifyOnly) {
+                                             bool VerifyOnly,
+                                             bool TreatUnavailableAsInvalid) {
   InitializationKind Kind = InitializationKind::CreateValue(Loc, Loc, Loc,
                                                             true);
   MultiExprArg SubInit;
@@ -443,7 +447,8 @@ ExprResult InitListChecker::PerformEmptyInit(Sema &SemaRef,
         InitSeq.InitializeFrom(
             SemaRef, Entity,
             InitializationKind::CreateValue(Loc, Loc, Loc, true),
-            MultiExprArg(), /*TopLevelOfInitList=*/false);
+            MultiExprArg(), /*TopLevelOfInitList=*/false,
+            TreatUnavailableAsInvalid);
         // Emit a warning for this.  System header warnings aren't shown
         // by default, but people working on system headers should see it.
         if (!VerifyOnly) {
@@ -480,7 +485,8 @@ void InitListChecker::CheckEmptyInitializable(const InitializedEntity &Entity,
                                               SourceLocation Loc) {
   assert(VerifyOnly &&
          "CheckEmptyInitializable is only inteded for verification mode.");
-  if (PerformEmptyInit(SemaRef, Loc, Entity, /*VerifyOnly*/true).isInvalid())
+  if (PerformEmptyInit(SemaRef, Loc, Entity, /*VerifyOnly*/true,
+                       TreatUnavailableAsInvalid).isInvalid())
     hadError = true;
 }
 
@@ -497,7 +503,8 @@ void InitListChecker::FillInEmptyInitForBase(
     ExprResult BaseInit =
         FillWithNoInit ? new (SemaRef.Context) NoInitExpr(Base.getType())
                        : PerformEmptyInit(SemaRef, ILE->getLocEnd(), BaseEntity,
-                                          /*VerifyOnly*/ false);
+                                          /*VerifyOnly*/ false,
+                                          TreatUnavailableAsInvalid);
     if (BaseInit.isInvalid()) {
       hadError = true;
       return;
@@ -572,7 +579,8 @@ void InitListChecker::FillInEmptyInitForField(unsigned Init, FieldDecl *Field,
     }
 
     ExprResult MemberInit = PerformEmptyInit(SemaRef, Loc, MemberEntity,
-                                             /*VerifyOnly*/false);
+                                             /*VerifyOnly*/false,
+                                             TreatUnavailableAsInvalid);
     if (MemberInit.isInvalid()) {
       hadError = true;
       return;
@@ -709,7 +717,8 @@ InitListChecker::FillInEmptyInitializations(const InitializedEntity &Entity,
       else {
         ExprResult ElementInit = PerformEmptyInit(SemaRef, ILE->getLocEnd(),
                                                   ElementEntity,
-                                                  /*VerifyOnly*/false);
+                                                  /*VerifyOnly*/false,
+                                                  TreatUnavailableAsInvalid);
         if (ElementInit.isInvalid()) {
           hadError = true;
           return;
@@ -757,8 +766,10 @@ InitListChecker::FillInEmptyInitializations(const InitializedEntity &Entity,
 
 InitListChecker::InitListChecker(Sema &S, const InitializedEntity &Entity,
                                  InitListExpr *IL, QualType &T,
-                                 bool VerifyOnly)
-  : SemaRef(S), VerifyOnly(VerifyOnly) {
+                                 bool VerifyOnly,
+                                 bool TreatUnavailableAsInvalid)
+  : SemaRef(S), VerifyOnly(VerifyOnly),
+    TreatUnavailableAsInvalid(TreatUnavailableAsInvalid) {
   // FIXME: Check that IL isn't already the semantic form of some other
   // InitListExpr. If it is, we'd create a broken AST.
 
@@ -1852,7 +1863,7 @@ void InitListChecker::CheckStructUnionTypes(
     // Make sure we can use this declaration.
     bool InvalidUse;
     if (VerifyOnly)
-      InvalidUse = !SemaRef.CanUseDecl(*Field);
+      InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
     else
       InvalidUse = SemaRef.DiagnoseUseOfDecl(*Field,
                                           IList->getInit(Index)->getLocStart());
@@ -2256,7 +2267,7 @@ InitListChecker::CheckDesignatedInitializer(const InitializedEntity &Entity,
     // Make sure we can use this declaration.
     bool InvalidUse;
     if (VerifyOnly)
-      InvalidUse = !SemaRef.CanUseDecl(*Field);
+      InvalidUse = !SemaRef.CanUseDecl(*Field, TreatUnavailableAsInvalid);
     else
       InvalidUse = SemaRef.DiagnoseUseOfDecl(*Field, D->getFieldLoc());
     if (InvalidUse) {
@@ -3387,7 +3398,8 @@ static void TryListInitialization(Sema &S,
                                   const InitializedEntity &Entity,
                                   const InitializationKind &Kind,
                                   InitListExpr *InitList,
-                                  InitializationSequence &Sequence);
+                                  InitializationSequence &Sequence,
+                                  bool TreatUnavailableAsInvalid);
 
 /// \brief When initializing from init list via constructor, handle
 /// initialization of an object of type std::initializer_list<T>.
@@ -3397,7 +3409,8 @@ static void TryListInitialization(Sema &S,
 static bool TryInitializerListConstruction(Sema &S,
                                            InitListExpr *List,
                                            QualType DestType,
-                                           InitializationSequence &Sequence) {
+                                           InitializationSequence &Sequence,
+                                           bool TreatUnavailableAsInvalid) {
   QualType E;
   if (!S.isStdInitializerList(DestType, &E))
     return false;
@@ -3416,7 +3429,8 @@ static bool TryInitializerListConstruction(Sema &S,
       InitializedEntity::InitializeTemporary(ArrayType);
   InitializationKind Kind =
       InitializationKind::CreateDirectList(List->getExprLoc());
-  TryListInitialization(S, HiddenArray, Kind, List, Sequence);
+  TryListInitialization(S, HiddenArray, Kind, List, Sequence,
+                        TreatUnavailableAsInvalid);
   if (Sequence)
     Sequence.AddStdInitializerListConstructionStep(DestType);
   return true;
@@ -3670,7 +3684,8 @@ static void TryReferenceListInitialization(Sema &S,
                                            const InitializedEntity &Entity,
                                            const InitializationKind &Kind,
                                            InitListExpr *InitList,
-                                           InitializationSequence &Sequence) {
+                                           InitializationSequence &Sequence,
+                                           bool TreatUnavailableAsInvalid) {
   // First, catch C++03 where this isn't possible.
   if (!S.getLangOpts().CPlusPlus11) {
     Sequence.SetFailed(InitializationSequence::FK_ReferenceBindingToInitList);
@@ -3726,7 +3741,8 @@ static void TryReferenceListInitialization(Sema &S,
   // Not reference-related. Create a temporary and bind to that.
   InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(cv1T1);
 
-  TryListInitialization(S, TempEntity, Kind, InitList, Sequence);
+  TryListInitialization(S, TempEntity, Kind, InitList, Sequence,
+                        TreatUnavailableAsInvalid);
   if (Sequence) {
     if (DestType->isRValueReferenceType() ||
         (T1Quals.hasConst() && !T1Quals.hasVolatile()))
@@ -3742,7 +3758,8 @@ static void TryListInitialization(Sema &S,
                                   const InitializedEntity &Entity,
                                   const InitializationKind &Kind,
                                   InitListExpr *InitList,
-                                  InitializationSequence &Sequence) {
+                                  InitializationSequence &Sequence,
+                                  bool TreatUnavailableAsInvalid) {
   QualType DestType = Entity.getType();
 
   // C++ doesn't allow scalar initialization with more than one argument.
@@ -3753,7 +3770,8 @@ static void TryListInitialization(Sema &S,
     return;
   }
   if (DestType->isReferenceType()) {
-    TryReferenceListInitialization(S, Entity, Kind, InitList, Sequence);
+    TryReferenceListInitialization(S, Entity, Kind, InitList, Sequence,
+                                   TreatUnavailableAsInvalid);
     return;
   }
 
@@ -3797,7 +3815,8 @@ static void TryListInitialization(Sema &S,
                                                    InitList->getRBraceLoc())
                 : Kind;
         Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
-                                /*TopLevelOfInitList*/ true);
+                                /*TopLevelOfInitList*/ true,
+                                TreatUnavailableAsInvalid);
 
         // TryStringLiteralInitialization() (in InitializeFrom()) will fail if
         // the element is not an appropriately-typed string literal, in which
@@ -3829,7 +3848,8 @@ static void TryListInitialization(Sema &S,
 
       //   - Otherwise, if T is a specialization of std::initializer_list<E>,
       //     an initializer_list object constructed [...]
-      if (TryInitializerListConstruction(S, InitList, DestType, Sequence))
+      if (TryInitializerListConstruction(S, InitList, DestType, Sequence,
+                                         TreatUnavailableAsInvalid))
         return;
 
       //   - Otherwise, if T is a class type, constructors are considered.
@@ -3865,14 +3885,15 @@ static void TryListInitialization(Sema &S,
             : Kind;
     Expr *SubInit[1] = { InitList->getInit(0) };
     Sequence.InitializeFrom(S, Entity, SubKind, SubInit,
-                            /*TopLevelOfInitList*/true);
+                            /*TopLevelOfInitList*/true,
+                            TreatUnavailableAsInvalid);
     if (Sequence)
       Sequence.RewrapReferenceInitList(Entity.getType(), InitList);
     return;
   }
 
   InitListChecker CheckInitList(S, Entity, InitList,
-          DestType, /*VerifyOnly=*/true);
+          DestType, /*VerifyOnly=*/true, TreatUnavailableAsInvalid);
   if (CheckInitList.HadError()) {
     Sequence.SetFailed(InitializationSequence::FK_ListInitializationFailed);
     return;
@@ -4877,9 +4898,11 @@ InitializationSequence::InitializationSequence(Sema &S,
                                                const InitializedEntity &Entity,
                                                const InitializationKind &Kind,
                                                MultiExprArg Args,
-                                               bool TopLevelOfInitList)
+                                               bool TopLevelOfInitList,
+                                               bool TreatUnavailableAsInvalid)
     : FailedCandidateSet(Kind.getLocation(), OverloadCandidateSet::CSK_Normal) {
-  InitializeFrom(S, Entity, Kind, Args, TopLevelOfInitList);
+  InitializeFrom(S, Entity, Kind, Args, TopLevelOfInitList,
+                 TreatUnavailableAsInvalid);
 }
 
 /// Tries to get a FunctionDecl out of `E`. If it succeeds and we can take the
@@ -4897,7 +4920,8 @@ void InitializationSequence::InitializeFrom(Sema &S,
                                             const InitializedEntity &Entity,
                                             const InitializationKind &Kind,
                                             MultiExprArg Args,
-                                            bool TopLevelOfInitList) {
+                                            bool TopLevelOfInitList,
+                                            bool TreatUnavailableAsInvalid) {
   ASTContext &Context = S.Context;
 
   // Eliminate non-overload placeholder types in the arguments.  We
@@ -4951,7 +4975,8 @@ void InitializationSequence::InitializeFrom(Sema &S,
   //       object is list-initialized (8.5.4).
   if (Kind.getKind() != InitializationKind::IK_Direct) {
     if (InitListExpr *InitList = dyn_cast_or_null<InitListExpr>(Initializer)) {
-      TryListInitialization(S, Entity, Kind, InitList, *this);
+      TryListInitialization(S, Entity, Kind, InitList, *this,
+                            TreatUnavailableAsInvalid);
       return;
     }
   }
@@ -5035,7 +5060,7 @@ void InitializationSequence::InitializeFrom(Sema &S,
              Entity.getKind() == InitializedEntity::EK_Member &&
              Initializer && isa<InitListExpr>(Initializer)) {
       TryListInitialization(S, Entity, Kind, cast<InitListExpr>(Initializer),
-                            *this);
+                            *this, TreatUnavailableAsInvalid);
       AddParenthesizedArrayInitStep(DestType);
     } else if (DestAT->getElementType()->isCharType())
       SetFailed(FK_ArrayNeedsInitListOrStringLiteral);
@@ -6581,7 +6606,8 @@ InitializationSequence::Perform(Sema &S,
       InitializedEntity TempEntity = InitializedEntity::InitializeTemporary(Ty);
       InitializedEntity InitEntity = IsTemporary ? TempEntity : Entity;
       InitListChecker PerformInitList(S, InitEntity,
-          InitList, Ty, /*VerifyOnly=*/false);
+          InitList, Ty, /*VerifyOnly=*/false,
+          /*TreatUnavailableAsInvalid=*/false);
       if (PerformInitList.HadError())
         return ExprError();
 
@@ -6952,7 +6978,8 @@ static void diagnoseListInit(Sema &S, const InitializedEntity &Entity,
   }
 
   InitListChecker DiagnoseInitList(S, Entity, InitList, DestType,
-                                   /*VerifyOnly=*/false);
+                                   /*VerifyOnly=*/false,
+                                   /*TreatUnavailableAsInvalid=*/false);
   assert(DiagnoseInitList.HadError() &&
          "Inconsistent init list check result.");
 }