More coherent diagnostic attempting to assign to a member of a const object returned

from an objective-c message: // rdar://9005189

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@128348 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/AST/Expr.h b/include/clang/AST/Expr.h
index 35264b820daff38d606f9a1bade95d3e96c5b38b..a6c3d49a2fe6b5e0b5b810eaae809300ea9e50f9 100644 (file)
--- a/include/clang/AST/Expr.h
+++ b/include/clang/AST/Expr.h
@@ -173,6 +173,7 @@ public:
     LV_IncompleteVoidType,
     LV_DuplicateVectorComponents,
     LV_InvalidExpression,
+    LV_InvalidMessageExpression,
     LV_MemberFunction,
     LV_SubObjCPropertySetting,
     LV_ClassTemporary
@@ -204,6 +205,7 @@ public:
     MLV_NoSetterProperty,
     MLV_MemberFunction,
     MLV_SubObjCPropertySetting,
+    MLV_InvalidMessageExpression,
     MLV_ClassTemporary
   };
   isModifiableLvalueResult isModifiableLvalue(ASTContext &Ctx,
@@ -223,6 +225,7 @@ public:
       CL_MemberFunction, // An expression referring to a member function
       CL_SubObjCPropertySetting,
       CL_ClassTemporary, // A prvalue of class type
+      CL_ObjCMessageRValue, // ObjC message is an rvalue
       CL_PRValue // A prvalue for any other reason, of any other type
     };
     /// \brief The results of modification testing.

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index cee572e7a2abab170db0f66310aeb7ebd4d1e61a..8ab9ff1e0b4ec1e7841affe36d197066e96462b7 100644 (file)
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2697,6 +2697,8 @@ def ext_gnu_ptr_func_arith : Extension<
   InGroup<PointerArith>;
 def error_readonly_property_assignment : Error<
   "assigning to property with 'readonly' attribute not allowed">;
+def error_readonly_message_assignment : Error<
+  "assigning to 'readonly' return result of an objective-c message not allowed">;
 def ext_integer_increment_complex : Extension<
   "ISO C does not support '++'/'--' on complex integer type %0">;
 def ext_integer_complement_complex : Extension<

diff --git a/lib/AST/ExprClassification.cpp b/lib/AST/ExprClassification.cpp
index 376792223ad78992c7110d4bfd874c58fd311e09..f90d59f5052a76ffb89d72835c7cc3f42b13d20c 100644 (file)
--- a/lib/AST/ExprClassification.cpp
+++ b/lib/AST/ExprClassification.cpp
@@ -75,6 +75,7 @@ Cl Expr::ClassifyImpl(ASTContext &Ctx, SourceLocation *Loc) const {
   case Cl::CL_MemberFunction:
   case Cl::CL_SubObjCPropertySetting:
   case Cl::CL_ClassTemporary:
+  case Cl::CL_ObjCMessageRValue:
   case Cl::CL_PRValue: assert(getValueKind() == VK_RValue); break;
   }
 
@@ -293,7 +294,8 @@ static Cl::Kinds ClassifyInternal(ASTContext &Ctx, const Expr *E) {
   case Expr::ObjCMessageExprClass:
     if (const ObjCMethodDecl *Method =
           cast<ObjCMessageExpr>(E)->getMethodDecl()) {
-      return ClassifyUnnamed(Ctx, Method->getResultType());
+      Cl::Kinds kind = ClassifyUnnamed(Ctx, Method->getResultType());
+      return (kind == Cl::CL_PRValue) ? Cl::CL_ObjCMessageRValue : kind;
     }
     return Cl::CL_PRValue;
       
@@ -551,6 +553,7 @@ Expr::LValueClassification Expr::ClassifyLValue(ASTContext &Ctx) const {
   case Cl::CL_MemberFunction: return LV_MemberFunction;
   case Cl::CL_SubObjCPropertySetting: return LV_SubObjCPropertySetting;
   case Cl::CL_ClassTemporary: return LV_ClassTemporary;
+  case Cl::CL_ObjCMessageRValue: return LV_InvalidMessageExpression;
   case Cl::CL_PRValue: return LV_InvalidExpression;
   }
   llvm_unreachable("Unhandled kind");
@@ -569,6 +572,7 @@ Expr::isModifiableLvalue(ASTContext &Ctx, SourceLocation *Loc) const {
   case Cl::CL_MemberFunction: return MLV_MemberFunction;
   case Cl::CL_SubObjCPropertySetting: return MLV_SubObjCPropertySetting;
   case Cl::CL_ClassTemporary: return MLV_ClassTemporary;
+  case Cl::CL_ObjCMessageRValue: return MLV_InvalidMessageExpression;
   case Cl::CL_PRValue:
     return VC.getModifiable() == Cl::CM_LValueCast ?
       MLV_LValueCast : MLV_InvalidExpression;

diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index dbddc384512536076463b54166467c44a0837770..dd81b389327137072d8c40cb619909a3cac1c534 100644 (file)
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -7378,6 +7378,20 @@ static bool IsReadonlyProperty(Expr *E, Sema &S) {
   return false;
 }
 
+static bool IsReadonlyMessage(Expr *E, Sema &S) {
+  if (E->getStmtClass() != Expr::MemberExprClass) 
+    return false;
+  const MemberExpr *ME = cast<MemberExpr>(E);
+  NamedDecl *Member = ME->getMemberDecl();
+  if (isa<FieldDecl>(Member)) {
+    Expr *Base = ME->getBase()->IgnoreParenImpCasts();
+    if (Base->getStmtClass() != Expr::ObjCMessageExprClass)
+      return false;
+    return cast<ObjCMessageExpr>(Base)->getMethodDecl() != 0;
+  }
+  return false;
+}
+
 /// CheckForModifiableLvalue - Verify that E is a modifiable lvalue.  If not,
 /// emit an error and return true.  If so, return false.
 static bool CheckForModifiableLvalue(Expr *E, SourceLocation Loc, Sema &S) {
@@ -7386,6 +7400,8 @@ static bool CheckForModifiableLvalue(Expr *E, SourceLocation Loc, Sema &S) {
                                                               &Loc);
   if (IsLV == Expr::MLV_Valid && IsReadonlyProperty(E, S))
     IsLV = Expr::MLV_ReadonlyProperty;
+  else if (IsLV == Expr::MLV_ClassTemporary && IsReadonlyMessage(E, S))
+    IsLV = Expr::MLV_InvalidMessageExpression;
   if (IsLV == Expr::MLV_Valid)
     return false;
 
@@ -7428,6 +7444,9 @@ static bool CheckForModifiableLvalue(Expr *E, SourceLocation Loc, Sema &S) {
   case Expr::MLV_NoSetterProperty:
     Diag = diag::error_nosetter_property_assignment;
     break;
+  case Expr::MLV_InvalidMessageExpression:
+    Diag = diag::error_readonly_message_assignment;
+    break;
   case Expr::MLV_SubObjCPropertySetting:
     Diag = diag::error_no_subobject_property_setting;
     break;
@@ -7812,7 +7831,7 @@ static QualType CheckAddressOfOperand(Sema &S, Expr *OrigOp,
   ValueDecl *dcl = getPrimaryDecl(op);
   Expr::LValueClassification lval = op->ClassifyLValue(S.Context);
 
-  if (lval == Expr::LV_ClassTemporary) {
+  if (lval == Expr::LV_ClassTemporary) { 
     bool sfinae = S.isSFINAEContext();
     S.Diag(OpLoc, sfinae ? diag::err_typecheck_addrof_class_temporary
                          : diag::ext_typecheck_addrof_class_temporary)

diff --git a/test/SemaObjC/assign-rvalue-message.m b/test/SemaObjC/assign-rvalue-message.m
new file mode 100644 (file)
index 0000000..7e05c89
--- /dev/null
+++ b/test/SemaObjC/assign-rvalue-message.m
@@ -0,0 +1,24 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -fsyntax-only -verify -fobjc-nonfragile-abi %s
+// RUN: %clang_cc1 -x objective-c++ -triple x86_64-apple-darwin10 -fsyntax-only -verify -fobjc-nonfragile-abi %s
+// rdar://9005189
+
+@interface Foo 
+@end
+
+struct Bar {
+    int x;
+};
+
+@implementation Foo {
+    struct Bar bar;
+}
+
+- (const struct Bar)bar {
+    return bar;
+}
+
+- (void)baz {
+    bar.x = 0;
+    [self bar].x = 10; // expected-error {{assigning to 'readonly' return result of an objective-c message not allowed}}
+}
+@end