re PR c++/28584 (Cast to pointer from integer of different size)

2010-04-09  Manuel López-Ibáñez  <manu@gcc.gnu.org>

	PR c++/28584
	* c.opt (Wint-to-pointer-cast): Available in C++.
	* doc/invoke.texi (Wint-to-pointer-cast): Available in C++.
cp/
	* typeck.c (cp_build_c_cast): Warn for casting integer to larger
	pointer type.
testsuite/
	* gcc.dg/Wint-to-pointer-cast-1.c: Move to...
	* c-c++-common/Wint-to-pointer-cast-1.c: ...  here.
	* gcc.dg/Wint-to-pointer-cast-2.c: Move to...	
	* c-c++-common/Wint-to-pointer-cast-2.c: ...  here.
	* gcc.dg/Wint-to-pointer-cast-3.c: Move to...	
	* c-c++-common/Wint-to-pointer-cast-3.c: ...  here. Update.
	* g++.old-deja/g++.mike/warn1.C: Add -Wno-int-to-pointer-cast.
	* g++.dg/other/increment1.C: Likewise.

From-SVN: r158150

gcc/ChangeLog

@@ -1,3 +1,9 @@
+2010-04-09  Manuel López-Ibáñez  <manu@gcc.gnu.org>
+
+	PR c++/28584
+	* c.opt (Wint-to-pointer-cast): Available in C++.
+	* doc/invoke.texi (Wint-to-pointer-cast): Available in C++.
+
 2010-04-08  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* tree.h (TREE_ADDRESSABLE): Document its effect for function types.

gcc/c.opt

@@ -277,7 +277,7 @@ Wimport
 C ObjC C++ ObjC++ Undocumented
 
 Wint-to-pointer-cast
-C ObjC Var(warn_int_to_pointer_cast) Init(1) Warning
+C ObjC C++ ObjC++ Var(warn_int_to_pointer_cast) Init(1) Warning
 Warn when there is a cast to a pointer from an integer of a different size
 
 Winvalid-offsetof

gcc/cp/ChangeLog

@@ -1,3 +1,9 @@
+2010-04-09  Manuel López-Ibáñez  <manu@gcc.gnu.org>
+
+	PR c++/28584
+	* typeck.c (cp_build_c_cast): Warn for casting integer to larger
+	pointer type.
+
 2010-04-07  Jason Merrill  <jason@redhat.com>
 
 	PR c++/43016

gcc/cp/typeck.c

@@ -6289,6 +6289,15 @@ cp_build_c_cast (tree type, tree expr, tsubst_flags_t complain)
       return error_mark_node;
     }
 
+  if (TREE_CODE (type) == POINTER_TYPE
+      && TREE_CODE (TREE_TYPE (value)) == INTEGER_TYPE
+      /* Casting to an integer of smaller size is an error detected elsewhere.  */
+      && TYPE_PRECISION (type) > TYPE_PRECISION (TREE_TYPE (value))
+      /* Don't warn about converting any constant.  */
+      && !TREE_CONSTANT (value))
+    warning_at (input_location, OPT_Wint_to_pointer_cast, 
+		"cast to pointer from integer of different size");
+
   /* A C-style cast can be a const_cast.  */
   result = build_const_cast_1 (type, value, /*complain=*/false,
 			       &valid_p);

gcc/doc/invoke.texi

@@ -4284,11 +4284,13 @@ warning about it.
 The restrictions on @samp{offsetof} may be relaxed in a future version
 of the C++ standard.
 
-@item -Wno-int-to-pointer-cast @r{(C and Objective-C only)}
+@item -Wno-int-to-pointer-cast
 @opindex Wno-int-to-pointer-cast
 @opindex Wint-to-pointer-cast
 Suppress warnings from casts to pointer type of an integer of a
-different size.
+different size. In C++, casting to a pointer type of smaller size is
+an error. @option{Wint-to-pointer-cast} is enabled by default.
+
 
 @item -Wno-pointer-to-int-cast @r{(C and Objective-C only)}
 @opindex Wno-pointer-to-int-cast

gcc/testsuite/ChangeLog

@@ -1,3 +1,15 @@
+2010-04-09  Manuel López-Ibáñez  <manu@gcc.gnu.org>
+
+	PR c++/28584
+	* gcc.dg/Wint-to-pointer-cast-1.c: Move to...
+	* c-c++-common/Wint-to-pointer-cast-1.c: ...  here.
+	* gcc.dg/Wint-to-pointer-cast-2.c: Move to...	
+	* c-c++-common/Wint-to-pointer-cast-2.c: ...  here.
+	* gcc.dg/Wint-to-pointer-cast-3.c: Move to...	
+	* c-c++-common/Wint-to-pointer-cast-3.c: ...  here. Update.
+	* g++.old-deja/g++.mike/warn1.C: Add -Wno-int-to-pointer-cast.
+	* g++.dg/other/increment1.C: Likewise.
+
 2010-04-09  Tobias Burnus  <burnus@net-b.de>
 
 	PR fortran/18918

gcc/testsuite/c-c++-common/Wint-to-pointer-cast-3.c

@@ -16,5 +16,7 @@ void *p;
 char
 g (void)
 {
-  return (char) p; /* { dg-warning "cast from pointer to integer of different size" } */
+  return (char) p;
+/* { dg-warning "cast from pointer to integer of different size" "" { target c } 19 } */
+/* { dg-error "cast from 'void\\*' to 'char' loses precision" "" { target c++ } 19 } */
 }

gcc/testsuite/g++.dg/other/increment1.C

@@ -1,5 +1,6 @@
 // PR c++/37561
 // { dg-do compile }
+// { dg-options "-Wno-int-to-pointer-cast" }
 
 __PTRDIFF_TYPE__ p;
 char q;

gcc/testsuite/g++.old-deja/g++.mike/warn1.C

@@ -1,5 +1,5 @@
 // { dg-do assemble  }
-// { dg-options "-Wall" }
+// { dg-options "-Wall -Wno-int-to-pointer-cast" }
 
 typedef char * charptr;
 typedef __SIZE_TYPE__ size_t;