PR c++/28584 Cast to pointer from integer of different size
Manuel López-Ibáñez
lopezibanez@gmail.com
Mon Feb 22 19:39:00 GMT 2010
Bootstrapped and regression tested x86_64-unknown-linux-gnu.
OK for 4.5 or 4.6?
2010-02-22 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.
-------------- next part --------------
Index: gcc/doc/invoke.texi
===================================================================
--- gcc/doc/invoke.texi (revision 156927)
+++ gcc/doc/invoke.texi (working copy)
@@ -4219,15 +4219,17 @@ writing nonportable code and who have de
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
@opindex Wpointer-to-int-cast
Suppress warnings from casts from a pointer to an integer type of a
Index: gcc/testsuite/gcc.dg/Wint-to-pointer-cast-1.c
===================================================================
--- gcc/testsuite/gcc.dg/Wint-to-pointer-cast-1.c (revision 156927)
+++ gcc/testsuite/gcc.dg/Wint-to-pointer-cast-1.c (working copy)
@@ -1,12 +0,0 @@
-/* Test -Wint-to-pointer-cast - on by default. */
-/* Origin: Joseph Myers <joseph@codesourcery.com> */
-/* { dg-do compile } */
-/* { dg-options "" } */
-
-char c;
-
-void *
-f (void)
-{
- return (void *) c; /* { dg-warning "cast to pointer from integer of different size" } */
-}
Index: gcc/testsuite/gcc.dg/Wint-to-pointer-cast-2.c
===================================================================
--- gcc/testsuite/gcc.dg/Wint-to-pointer-cast-2.c (revision 156927)
+++ gcc/testsuite/gcc.dg/Wint-to-pointer-cast-2.c (working copy)
@@ -1,12 +0,0 @@
-/* Test -Wint-to-pointer-cast. */
-/* Origin: Joseph Myers <joseph@codesourcery.com> */
-/* { dg-do compile } */
-/* { dg-options "-Wint-to-pointer-cast" } */
-
-char c;
-
-void *
-f (void)
-{
- return (void *) c; /* { dg-warning "cast to pointer from integer of different size" } */
-}
Index: gcc/testsuite/gcc.dg/Wint-to-pointer-cast-3.c
===================================================================
--- gcc/testsuite/gcc.dg/Wint-to-pointer-cast-3.c (revision 156927)
+++ gcc/testsuite/gcc.dg/Wint-to-pointer-cast-3.c (working copy)
@@ -1,20 +0,0 @@
-/* Test -Wno-int-to-pointer-cast. */
-/* Origin: Joseph Myers <joseph@codesourcery.com> */
-/* { dg-do compile } */
-/* { dg-options "-Wno-int-to-pointer-cast" } */
-
-char c;
-
-void *
-f (void)
-{
- return (void *) c;
-}
-
-void *p;
-
-char
-g (void)
-{
- return (char) p; /* { dg-warning "cast from pointer to integer of different size" } */
-}
Index: gcc/testsuite/g++.old-deja/g++.mike/warn1.C
===================================================================
--- gcc/testsuite/g++.old-deja/g++.mike/warn1.C (revision 156927)
+++ gcc/testsuite/g++.old-deja/g++.mike/warn1.C (working copy)
@@ -1,7 +1,7 @@
// { dg-do assemble }
-// { dg-options "-Wall" }
+// { dg-options "-Wall -Wno-int-to-pointer-cast" }
typedef char * charptr;
typedef __SIZE_TYPE__ size_t;
char c[]={'A','B','C','D'};
int i=size_t(&c);
Index: gcc/testsuite/g++.dg/other/increment1.C
===================================================================
--- gcc/testsuite/g++.dg/other/increment1.C (revision 156927)
+++ gcc/testsuite/g++.dg/other/increment1.C (working copy)
@@ -1,7 +1,8 @@
// PR c++/37561
// { dg-do compile }
+// { dg-options "-Wno-int-to-pointer-cast" }
__PTRDIFF_TYPE__ p;
char q;
void
Property changes on: gcc/testsuite/c-c++-common/Wint-to-pointer-cast-1.c
___________________________________________________________________
Added: svn:mergeinfo
Property changes on: gcc/testsuite/c-c++-common/Wint-to-pointer-cast-2.c
___________________________________________________________________
Added: svn:mergeinfo
Index: gcc/testsuite/c-c++-common/Wint-to-pointer-cast-3.c
===================================================================
--- gcc/testsuite/c-c++-common/Wint-to-pointer-cast-3.c (revision 156927)
+++ gcc/testsuite/c-c++-common/Wint-to-pointer-cast-3.c (working copy)
@@ -14,7 +14,9 @@ f (void)
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 } */
}
Property changes on: gcc/testsuite/c-c++-common/Wint-to-pointer-cast-3.c
___________________________________________________________________
Added: svn:mergeinfo
Index: gcc/cp/typeck.c
===================================================================
--- gcc/cp/typeck.c (revision 156927)
+++ gcc/cp/typeck.c (working copy)
@@ -6260,10 +6260,19 @@ cp_build_c_cast (tree type, tree expr, t
if (complain & tf_error)
error ("invalid cast to function type %qT", type);
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);
if (valid_p)
return result;
Index: gcc/c.opt
===================================================================
--- gcc/c.opt (revision 156927)
+++ gcc/c.opt (working copy)
@@ -271,11 +271,11 @@ Warn when a declaration does not specify
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
C++ ObjC++ Var(warn_invalid_offsetof) Init(1) Warning
Warn about invalid uses of the \"offsetof\" macro
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