[cfe-commits] r132191 - in /cfe/trunk: lib/Sema/JumpDiagnostics.cpp test/CXX/stmt.stmt/stmt.dcl/p3.cpp

[Douglas Gregor]

Author: dgregor
Date: Fri May 27 11:05:29 2011
New Revision: 132191

URL: http://llvm.org/viewvc/llvm-project?rev=132191&view=rev
Log:
Update the jump-scope checker for local variables with initializers,
so that it looks at the initializer of a local variable of class type
(or array thereof) to determine whether it's just an implicit
invocation of the trivial default constructor. Fixes PR10034.

Added:
    cfe/trunk/test/CXX/stmt.stmt/stmt.dcl/p3.cpp   (with props)
Modified:
    cfe/trunk/lib/Sema/JumpDiagnostics.cpp

Modified: cfe/trunk/lib/Sema/JumpDiagnostics.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/JumpDiagnostics.cpp?rev=132191&r1=132190&r2=132191&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/JumpDiagnostics.cpp (original)
+++ cfe/trunk/lib/Sema/JumpDiagnostics.cpp Fri May 27 11:05:29 2011
@@ -15,6 +15,7 @@
 #include "clang/Sema/SemaInternal.h"
 #include "clang/AST/DeclCXX.h"
 #include "clang/AST/Expr.h"
+#include "clang/AST/ExprCXX.h"
 #include "clang/AST/StmtObjC.h"
 #include "clang/AST/StmtCXX.h"
 #include "llvm/ADT/BitVector.h"
@@ -126,18 +127,48 @@
       InDiag = diag::note_protected_by_cleanup;
       OutDiag = diag::note_exits_cleanup;
     } else if (isCPlusPlus) {
-      // FIXME: In C++0x, we have to check more conditions than "did we
-      // just give it an initializer?". See 6.7p3.
-      if (VD->hasLocalStorage() && VD->hasInit())
-        InDiag = diag::note_protected_by_variable_init;
-
-      CanQualType T = VD->getType()->getCanonicalTypeUnqualified();
+      if (!VD->hasLocalStorage())
+        return std::make_pair(InDiag, OutDiag);
+      
+      ASTContext &Context = D->getASTContext();
+      QualType T = Context.getBaseElementType(VD->getType());
       if (!T->isDependentType()) {
-        while (CanQual<ArrayType> AT = T->getAs<ArrayType>())
-          T = AT->getElementType();
-        if (CanQual<RecordType> RT = T->getAs<RecordType>())
-          if (!cast<CXXRecordDecl>(RT->getDecl())->hasTrivialDestructor())
+        // C++0x [stmt.dcl]p3:
+        //   A program that jumps from a point where a variable with automatic
+        //   storage duration is not in scope to a point where it is in scope
+        //   is ill-formed unless the variable has scalar type, class type with
+        //   a trivial default constructor and a trivial destructor, a 
+        //   cv-qualified version of one of these types, or an array of one of
+        //   the preceding types and is declared without an initializer (8.5).
+        if (VD->hasLocalStorage() && Context.getLangOptions().CPlusPlus) {
+          // Check whether this is a C++ class.
+          CXXRecordDecl *Record = T->getAsCXXRecordDecl();
+          
+          if (const Expr *Init = VD->getInit()) {
+            bool CallsTrivialConstructor = false;
+            if (Record) {
+              // FIXME: With generalized initializer lists, this may
+              // classify "X x{};" as having no initializer.
+              if (const CXXConstructExpr *Construct 
+                                          = dyn_cast<CXXConstructExpr>(Init))
+                if (const CXXConstructorDecl *Constructor
+                                                  = Construct->getConstructor())
+                  if (Constructor->isDefaultConstructor() &&
+                      ((Context.getLangOptions().CPlusPlus0x &&
+                        Record->hasTrivialDefaultConstructor()) ||
+                       (!Context.getLangOptions().CPlusPlus0x &&
+                        Record->isPOD())))
+                    CallsTrivialConstructor = true;
+            }
+            
+            if (!CallsTrivialConstructor)
+              InDiag = diag::note_protected_by_variable_init;
+          }
+          
+          // Note whether we have a class with a non-trivial destructor.
+          if (Record && !Record->hasTrivialDestructor())
             OutDiag = diag::note_exits_dtor;
+        }
       }
     }
     

Added: cfe/trunk/test/CXX/stmt.stmt/stmt.dcl/p3.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/stmt.stmt/stmt.dcl/p3.cpp?rev=132191&view=auto
==============================================================================
--- cfe/trunk/test/CXX/stmt.stmt/stmt.dcl/p3.cpp (added)
+++ cfe/trunk/test/CXX/stmt.stmt/stmt.dcl/p3.cpp Fri May 27 11:05:29 2011
@@ -0,0 +1,26 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -std=c++0x -fsyntax-only -verify %s
+
+// PR10034
+struct X {};
+
+void exx(X) {}
+
+int main(int argc, char **argv)
+{
+ if (argc > 3)
+   goto end;
+
+ X x;
+ X xs[16];
+ exx(x);
+
+ end:
+   if (argc > 1) {
+   for (int i = 0; i < argc; ++i)
+   {
+
+   }
+   }
+   return 0;
+}

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