Re: Patch to fix Clang armv7 IRGen crash - PR17759

[jahanian]

On Dec 2, 2013, at 4:22 PM, Richard Smith <rich...@metafoo.co.uk> wrote: This is a frontend bug, not an IRGen bug; the test case is ill-formed. "return;" can be used in a constructor or destructor, but "return <_expression_-with-type-void>;" cannot. Ok thanks. Sema patch is attached. Please review. - Fariborz

Index: include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- include/clang/Basic/DiagnosticSemaKinds.td  (revision 196171)
+++ include/clang/Basic/DiagnosticSemaKinds.td  (working copy)
@@ -6426,6 +6426,8 @@
 def err_return_init_list : Error<
   "%select{void function|void method|constructor|destructor}1 %0 "
   "must not return a value">;
+def err_ctor_dtor_returns_void : Error<
+  "%select{constructor|destructor}1 %0 must not return void expression">;
 def warn_noreturn_function_has_return_expr : Warning<
   "function %0 declared 'noreturn' should not return">,
   InGroup<InvalidNoreturn>;
Index: lib/Sema/SemaStmt.cpp
===================================================================
--- lib/Sema/SemaStmt.cpp       (revision 196171)
+++ lib/Sema/SemaStmt.cpp       (working copy)
@@ -2801,8 +2801,14 @@
       } else if (!RetValExp->isTypeDependent()) {
         // C99 6.8.6.4p1 (ext_ since GCC warns)
         unsigned D = diag::ext_return_has_expr;
-        if (RetValExp->getType()->isVoidType())
-          D = diag::ext_return_has_void_expr;
+        if (RetValExp->getType()->isVoidType()) {
+          NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
+          if (isa<CXXConstructorDecl>(CurDecl) ||
+              isa<CXXDestructorDecl>(CurDecl))
+            D = diag::err_ctor_dtor_returns_void;
+          else
+            D = diag::ext_return_has_void_expr;
+        }
         else {
           ExprResult Result = Owned(RetValExp);
           Result = IgnoredValueConversions(Result.take());
@@ -2812,9 +2818,15 @@
           RetValExp = ImpCastExprToType(RetValExp,
                                         Context.VoidTy, CK_ToVoid).take();
         }
-
+        // return of void in constructor/destructor is illegal in C++.
+        if (D == diag::err_ctor_dtor_returns_void) {
+          NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
+          Diag(ReturnLoc, D)
+            << CurDecl->getDeclName() << isa<CXXDestructorDecl>(CurDecl)
+            << RetValExp->getSourceRange();
+        }
         // return (some void expression); is legal in C++.
-        if (D != diag::ext_return_has_void_expr ||
+        else if (D != diag::ext_return_has_void_expr ||
             !getLangOpts().CPlusPlus) {
           NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
 
Index: test/SemaCXX/return.cpp
===================================================================
--- test/SemaCXX/return.cpp     (revision 196171)
+++ test/SemaCXX/return.cpp     (working copy)
@@ -102,3 +102,13 @@
     }
   };
 }
+
+// rdar://15366494
+// pr17759
+namespace ctor_returns_void {
+  void f() {}
+  struct S { 
+    S() { return f(); }; // expected-error {{constructor 'S' must not return 
void expression}}
+    ~S() { return f(); } // expected-error {{destructor '~S' must not return 
void expression}}
+  };
+}

On Mon, Dec 2, 2013 at 4:09 PM, jahanian <fjahan...@apple.com> wrote: This patch fixes a crash when generating IRGen for armv7 which has ABI of implicit return of 'this' for constructors. Please review. // rdar://15366494 - fariborz _______________________________________________ cfe-commits mailing list cfe-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits

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