Implement template instantiation for Objective-C++ message sends. We

support dependent receivers for class and instance messages, along
with dependent message arguments (of course), and check as much as we
can at template definition time.

This commit also deals with a subtle aspect of template instantiation
in Objective-C++, where the type 'T *' can morph from a dependent
PointerType into a non-dependent ObjCObjectPointer type.

llvm-svn: 102071

1 files changed, 37 insertions, 4 deletions

diff --git a/clang/lib/Sema/SemaExprObjC.cpp b/clang/lib/Sema/SemaExprObjC.cpp
index e6884bac333..71833f254c4 100644
--- a/clang/lib/Sema/SemaExprObjC.cpp
+++ b/clang/lib/Sema/SemaExprObjC.cpp
@@ -177,8 +177,12 @@ bool Sema::CheckMessageArgumentTypes(Expr **Args, unsigned NumArgs,
                                      QualType &ReturnType) {
   if (!Method) {
     // Apply default argument promotion as for (C99 6.5.2.2p6).
-    for (unsigned i = 0; i != NumArgs; i++)
+    for (unsigned i = 0; i != NumArgs; i++) {
+      if (Args[i]->isTypeDependent())
+        continue;
+
       DefaultArgumentPromotion(Args[i]);
+    }
 
     unsigned DiagID = isClassMessage ? diag::warn_class_method_not_found :
                                        diag::warn_inst_method_not_found;
@@ -204,7 +208,12 @@ bool Sema::CheckMessageArgumentTypes(Expr **Args, unsigned NumArgs,
 
   bool IsError = false;
   for (unsigned i = 0; i < NumNamedArgs; i++) {
+    // We can't do any type-checking on a type-dependent argument.
+    if (Args[i]->isTypeDependent())
+      continue;
+
     Expr *argExpr = Args[i];
+
     ParmVarDecl *Param = Method->param_begin()[i];
     assert(argExpr && "CheckMessageArgumentTypes(): missing expression");
 
@@ -226,8 +235,12 @@ bool Sema::CheckMessageArgumentTypes(Expr **Args, unsigned NumArgs,
 
   // Promote additional arguments to variadic methods.
   if (Method->isVariadic()) {
-    for (unsigned i = NumNamedArgs; i < NumArgs; ++i)
+    for (unsigned i = NumNamedArgs; i < NumArgs; ++i) {
+      if (Args[i]->isTypeDependent())
+        continue;
+
       IsError |= DefaultVariadicArgumentPromotion(Args[i], VariadicMethod);
+    }
   } else {
     // Check for extra arguments to non-variadic methods.
     if (NumArgs != NumNamedArgs) {
@@ -677,8 +690,16 @@ Sema::OwningExprResult Sema::BuildClassMessage(TypeSourceInfo *ReceiverTypeInfo,
                                                SourceLocation SelectorLoc,
                                                SourceLocation RBracLoc,
                                                MultiExprArg ArgsIn) {
-  assert(!ReceiverType->isDependentType() && 
-         "Dependent class messages not yet implemented");
+  if (ReceiverType->isDependentType()) {
+    // If the receiver type is dependent, we can't type-check anything
+    // at this point. Build a dependent expression.
+    unsigned NumArgs = ArgsIn.size();
+    Expr **Args = reinterpret_cast<Expr **>(ArgsIn.release());
+    assert(SuperLoc.isInvalid() && "Message to super with dependent type");
+    return Owned(ObjCMessageExpr::Create(Context, ReceiverType, LBracLoc,
+                                         ReceiverTypeInfo, Sel, /*Method=*/0, 
+                                         Args, NumArgs, RBracLoc));
+  }
   
   SourceLocation Loc = SuperLoc.isValid()? SuperLoc
              : ReceiverTypeInfo->getTypeLoc().getSourceRange().getBegin();
@@ -802,6 +823,18 @@ Sema::OwningExprResult Sema::BuildInstanceMessage(ExprArg ReceiverE,
   // and determine receiver type.
   Expr *Receiver = ReceiverE.takeAs<Expr>();
   if (Receiver) {
+    if (Receiver->isTypeDependent()) {
+      // If the receiver is type-dependent, we can't type-check anything
+      // at this point. Build a dependent expression.
+      unsigned NumArgs = ArgsIn.size();
+      Expr **Args = reinterpret_cast<Expr **>(ArgsIn.release());
+      assert(SuperLoc.isInvalid() && "Message to super with dependent type");
+      return Owned(ObjCMessageExpr::Create(Context, Context.DependentTy,
+                                           LBracLoc, Receiver, Sel, 
+                                           /*Method=*/0, Args, NumArgs, 
+                                           RBracLoc));
+    }
+
     // If necessary, apply function/array conversion to the receiver.
     // C99 6.7.5.3p[7,8].
     DefaultFunctionArrayLvalueConversion(Receiver);