Make yet another placeholder type, this one marking that an expression is a bound

member function, i.e. something of the form 'x.f' where 'f' is a non-static
member function.  Diagnose this in the general case.  Some of the new diagnostics
are probably worse than the old ones, but we now get this right much more
universally, and there's certainly room for improvement in the diagnostics.

llvm-svn: 130239

1 files changed, 55 insertions, 81 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index c90c5132506..212f584f5fe 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -3934,12 +3934,20 @@ Sema::BuildMemberReferenceExpr(Expr *BaseExpr, QualType BaseExprType,
   }
 
   if (CXXMethodDecl *MemberFn = dyn_cast<CXXMethodDecl>(MemberDecl)) {
+    ExprValueKind valueKind;
+    QualType type;
+    if (MemberFn->isInstance()) {
+      valueKind = VK_RValue;
+      type = Context.BoundMemberTy;
+    } else {
+      valueKind = VK_LValue;
+      type = MemberFn->getType();
+    }
+
     MarkDeclarationReferenced(MemberLoc, MemberDecl);
     return Owned(BuildMemberExpr(Context, BaseExpr, IsArrow, SS,
                                  MemberFn, FoundDecl, MemberNameInfo,
-                                 MemberFn->getType(),
-                                 MemberFn->isInstance() ? VK_RValue : VK_LValue,
-                                 OK_Ordinary));
+                                 type, valueKind, OK_Ordinary));
   }
   assert(!isa<FunctionDecl>(MemberDecl) && "member function not C++ method?");
 
@@ -4051,6 +4059,8 @@ Sema::LookupMemberExpr(LookupResult &R, ExprResult &BaseExpr,
         << BaseType << int(IsArrow) << BaseExpr.get()->getSourceRange()
         << FixItHint::CreateReplacement(OpLoc, ".");
       IsArrow = false;
+    } else if (BaseType == Context.BoundMemberTy) {
+      goto fail;
     } else {
       Diag(MemberLoc, diag::err_typecheck_member_reference_arrow)
         << BaseType << BaseExpr.get()->getSourceRange();
@@ -4424,6 +4434,16 @@ Sema::LookupMemberExpr(LookupResult &R, ExprResult &BaseExpr,
       }
     } else if ((Fun = BaseType->getAs<FunctionType>())) {
       TryCall = true;
+    } else if (BaseType == Context.BoundMemberTy) {
+      // Look for the bound-member type.  If it's still overloaded,
+      // give up, although we probably should have fallen into the
+      // OverloadExpr case above if we actually have an overloaded
+      // bound member.
+      QualType fnType = Expr::findBoundMemberType(BaseExpr.get());
+      if (!fnType.isNull()) {
+        TryCall = true;
+        Fun = fnType->castAs<FunctionType>();
+      }
     }
 
     if (TryCall) {
@@ -4858,91 +4878,33 @@ Sema::ActOnCallExpr(Scope *S, Expr *Fn, SourceLocation LParenLoc,
       Fn = result.take();
     }
 
-    Expr *NakedFn = Fn->IgnoreParens();
-
-    // Determine whether this is a call to an unresolved member function.
-    if (UnresolvedMemberExpr *MemE = dyn_cast<UnresolvedMemberExpr>(NakedFn)) {
-      // If lookup was unresolved but not dependent (i.e. didn't find
-      // an unresolved using declaration), it has to be an overloaded
-      // function set, which means it must contain either multiple
-      // declarations (all methods or method templates) or a single
-      // method template.
-      assert((MemE->getNumDecls() > 1) ||
-             isa<FunctionTemplateDecl>(
-                                 (*MemE->decls_begin())->getUnderlyingDecl()));
-      (void)MemE;
-
+    if (Fn->getType() == Context.BoundMemberTy) {
       return BuildCallToMemberFunction(S, Fn, LParenLoc, Args, NumArgs,
                                        RParenLoc);
     }
+  }
+
+  // Check for overloaded calls.  This can happen even in C due to extensions.
+  if (Fn->getType() == Context.OverloadTy) {
+    OverloadExpr::FindResult find = OverloadExpr::find(Fn);
 
-    // Determine whether this is a call to a member function.
-    if (MemberExpr *MemExpr = dyn_cast<MemberExpr>(NakedFn)) {
-      NamedDecl *MemDecl = MemExpr->getMemberDecl();
-      if (isa<CXXMethodDecl>(MemDecl))
+    // We aren't supposed to apply this logic if there's an '&' involved.
+    if (!find.IsAddressOfOperand) {
+      OverloadExpr *ovl = find.Expression;
+      if (isa<UnresolvedLookupExpr>(ovl)) {
+        UnresolvedLookupExpr *ULE = cast<UnresolvedLookupExpr>(ovl);
+        return BuildOverloadedCallExpr(S, Fn, ULE, LParenLoc, Args, NumArgs,
+                                       RParenLoc, ExecConfig);
+      } else {
         return BuildCallToMemberFunction(S, Fn, LParenLoc, Args, NumArgs,
                                          RParenLoc);
-    }
-
-    // Determine whether this is a call to a pointer-to-member function.
-    if (BinaryOperator *BO = dyn_cast<BinaryOperator>(NakedFn)) {
-      if (BO->getOpcode() == BO_PtrMemD ||
-          BO->getOpcode() == BO_PtrMemI) {
-        if (const FunctionProtoType *FPT
-                                = BO->getType()->getAs<FunctionProtoType>()) {
-          QualType ResultTy = FPT->getCallResultType(Context);
-          ExprValueKind VK = Expr::getValueKindForType(FPT->getResultType());
-
-          // Check that the object type isn't more qualified than the
-          // member function we're calling.
-          Qualifiers FuncQuals = Qualifiers::fromCVRMask(FPT->getTypeQuals());
-          Qualifiers ObjectQuals 
-            = BO->getOpcode() == BO_PtrMemD
-                ? BO->getLHS()->getType().getQualifiers()
-                : BO->getLHS()->getType()->getAs<PointerType>()
-                                            ->getPointeeType().getQualifiers();
-
-          Qualifiers Difference = ObjectQuals - FuncQuals;
-          Difference.removeObjCGCAttr();
-          Difference.removeAddressSpace();
-          if (Difference) {
-            std::string QualsString = Difference.getAsString();
-            Diag(LParenLoc, diag::err_pointer_to_member_call_drops_quals)
-              << BO->getType().getUnqualifiedType()
-              << QualsString
-              << (QualsString.find(' ') == std::string::npos? 1 : 2);
-          }
-              
-          CXXMemberCallExpr *TheCall
-            = new (Context) CXXMemberCallExpr(Context, Fn, Args,
-                                              NumArgs, ResultTy, VK,
-                                              RParenLoc);
-
-          if (CheckCallReturnType(FPT->getResultType(),
-                                  BO->getRHS()->getSourceRange().getBegin(),
-                                  TheCall, 0))
-            return ExprError();
-
-          if (ConvertArgumentsForCall(TheCall, BO, 0, FPT, Args, NumArgs,
-                                      RParenLoc))
-            return ExprError();
-
-          return MaybeBindToTemporary(TheCall);
-        }
       }
     }
   }
 
   // If we're directly calling a function, get the appropriate declaration.
-  // Also, in C++, keep track of whether we should perform argument-dependent
-  // lookup and whether there were any explicitly-specified template arguments.
 
   Expr *NakedFn = Fn->IgnoreParens();
-  if (isa<UnresolvedLookupExpr>(NakedFn)) {
-    UnresolvedLookupExpr *ULE = cast<UnresolvedLookupExpr>(NakedFn);
-    return BuildOverloadedCallExpr(S, Fn, ULE, LParenLoc, Args, NumArgs,
-                                   RParenLoc, ExecConfig);
-  }
 
   NamedDecl *NDecl = 0;
   if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(NakedFn))
@@ -4951,6 +4913,8 @@ Sema::ActOnCallExpr(Scope *S, Expr *Fn, SourceLocation LParenLoc,
   
   if (isa<DeclRefExpr>(NakedFn))
     NDecl = cast<DeclRefExpr>(NakedFn)->getDecl();
+  else if (isa<MemberExpr>(NakedFn))
+    NDecl = cast<MemberExpr>(NakedFn)->getMemberDecl();
 
   return BuildResolvedCallExpr(Fn, NDecl, LParenLoc, Args, NumArgs, RParenLoc,
                                ExecConfig);
@@ -8282,6 +8246,11 @@ static QualType CheckAddressOfOperand(Sema &S, Expr *OrigOp,
     return S.Context.OverloadTy;
   if (OrigOp->getType() == S.Context.UnknownAnyTy)
     return S.Context.UnknownAnyTy;
+  if (OrigOp->getType() == S.Context.BoundMemberTy) {
+    S.Diag(OpLoc, diag::err_invalid_form_pointer_member_function)
+      << OrigOp->getSourceRange();
+    return QualType();
+  }
 
   assert(!OrigOp->getType()->isPlaceholderType());
 
@@ -10301,13 +10270,11 @@ ExprResult Sema::CheckBooleanCondition(Expr *E, SourceLocation Loc) {
   if (ParenExpr *parenE = dyn_cast<ParenExpr>(E))
     DiagnoseEqualityWithExtraParens(parenE);
 
-  if (!E->isTypeDependent()) {
-    if (E->isBoundMemberFunction(Context)) {
-      Diag(E->getLocStart(), diag::err_invalid_use_of_bound_member_func)
-        << E->getSourceRange();
-      return ExprError();
-    }
+  ExprResult result = CheckPlaceholderExpr(E);
+  if (result.isInvalid()) return ExprError();
+  E = result.take();
 
+  if (!E->isTypeDependent()) {
     if (getLangOptions().CPlusPlus)
       return CheckCXXBooleanCondition(E); // C++ 6.4p4
 
@@ -10728,6 +10695,13 @@ ExprResult Sema::CheckPlaceholderExpr(Expr *E) {
                                                              QualType(),
                                                    diag::err_ovl_unresolvable);
 
+  // Bound member functions.
+  if (type == Context.BoundMemberTy) {
+    Diag(E->getLocStart(), diag::err_invalid_use_of_bound_member_func)
+      << E->getSourceRange();
+    return ExprError();
+  }    
+
   // Expressions of unknown type.
   if (type == Context.UnknownAnyTy)
     return diagnoseUnknownAnyExpr(*this, E);