On Fri, Sep 30, 2016 at 05:48:03PM -0400, Jason Merrill wrote:
> On Fri, Sep 30, 2016 at 12:43 PM, Marek Polacek <pola...@redhat.com> wrote:
> > On Fri, Sep 23, 2016 at 10:31:33AM -0400, Jason Merrill wrote:
> >> On Fri, Sep 23, 2016 at 9:15 AM, Marek Polacek <pola...@redhat.com> wrote:
> >> > On Wed, Sep 21, 2016 at 03:52:09PM -0400, Jason Merrill wrote:
> >> >> On Mon, Sep 19, 2016 at 2:49 PM, Jason Merrill <ja...@redhat.com> wrote:
> >> >> > I suppose that an INTEGER_CST of character type is necessarily a
> >> >> > character constant, so adding a check for !char_type_p ought to do the
> >> >> > trick.
> >> >>
> >> >> Indeed it does. I'm checking this in:
> >> >
> >> > Nice, thanks. What about the original patch? We still need to warn
> >> > (or error for C++11) for pointer comparisons.
> >>
> >> If we still accept pointer comparisons in C++, that's another bug with
> >> treating \0 as a null pointer constant. This seems to be because
> >> ocp_convert of \0 to int produces an INTEGER_CST indistinguishable
> >> from literal 0.
> >
> > I was trying to fix this in ocp_convert, by using NOP_EXPRs, but that wasn't
> > successful. But since we're interested in ==/!=, I think this can be fixed
> > easily in cp_build_binary_op. Actually, all that seems to be needed is
> > using
> > orig_op as the argument to null_ptr_cst_p, but that wouldn't give the
> > correct
> > diagnostics, so I did this. By checking orig_op we can see if the operands
> > are
> > character literals or not, because orig_op is an operand before the default
> > conversions.
>
> What is wrong about the diagnostic from just using orig_op? "ISO C++
> forbids comparison between pointer and integer" seems fine to me, and
> will help the user to realize that they need to index off the pointer.
>
> I see that some of the calls to null_ptr_cst_p in cp_build_binary_op
> have already been changed to check orig_op*, but not all. Let's
> update the remaining calls, that should do the trick without adding a
> new error.
Here you go:
Bootstrapped/regtested on x86_64-linux and ppc64-linux, ok for trunk?
2016-10-01 Marek Polacek <pola...@redhat.com>
Core 903
* typeck.c (cp_build_binary_op): Pass original operands to
null_ptr_cst_p, not those after the default conversions.
* g++.dg/cpp0x/nullptr37.C: New test.
diff --git gcc/cp/typeck.c gcc/cp/typeck.c
index 617ca55..8b780be 100644
--- gcc/cp/typeck.c
+++ gcc/cp/typeck.c
@@ -4573,7 +4573,7 @@ cp_build_binary_op (location_t location,
|| code1 == COMPLEX_TYPE || code1 == ENUMERAL_TYPE))
short_compare = 1;
else if (((code0 == POINTER_TYPE || TYPE_PTRDATAMEM_P (type0))
- && null_ptr_cst_p (op1))
+ && null_ptr_cst_p (orig_op1))
/* Handle, eg, (void*)0 (c++/43906), and more. */
|| (code0 == POINTER_TYPE
&& TYPE_PTR_P (type1) && integer_zerop (op1)))
@@ -4587,7 +4587,7 @@ cp_build_binary_op (location_t location,
warn_for_null_address (location, op0, complain);
}
else if (((code1 == POINTER_TYPE || TYPE_PTRDATAMEM_P (type1))
- && null_ptr_cst_p (op0))
+ && null_ptr_cst_p (orig_op0))
/* Handle, eg, (void*)0 (c++/43906), and more. */
|| (code1 == POINTER_TYPE
&& TYPE_PTR_P (type0) && integer_zerop (op0)))
@@ -4604,7 +4604,7 @@ cp_build_binary_op (location_t location,
|| (TYPE_PTRDATAMEM_P (type0) && TYPE_PTRDATAMEM_P (type1)))
result_type = composite_pointer_type (type0, type1, op0, op1,
CPO_COMPARISON, complain);
- else if (null_ptr_cst_p (op0) && null_ptr_cst_p (op1))
+ else if (null_ptr_cst_p (orig_op0) && null_ptr_cst_p (orig_op1))
/* One of the operands must be of nullptr_t type. */
result_type = TREE_TYPE (nullptr_node);
else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
@@ -4623,7 +4623,7 @@ cp_build_binary_op (location_t location,
else
return error_mark_node;
}
- else if (TYPE_PTRMEMFUNC_P (type0) && null_ptr_cst_p (op1))
+ else if (TYPE_PTRMEMFUNC_P (type0) && null_ptr_cst_p (orig_op1))
{
if (TARGET_PTRMEMFUNC_VBIT_LOCATION
== ptrmemfunc_vbit_in_delta)
@@ -4664,7 +4664,7 @@ cp_build_binary_op (location_t location,
}
result_type = TREE_TYPE (op0);
}
- else if (TYPE_PTRMEMFUNC_P (type1) && null_ptr_cst_p (op0))
+ else if (TYPE_PTRMEMFUNC_P (type1) && null_ptr_cst_p (orig_op0))
return cp_build_binary_op (location, code, op1, op0, complain);
else if (TYPE_PTRMEMFUNC_P (type0) && TYPE_PTRMEMFUNC_P (type1))
{
@@ -4877,21 +4877,21 @@ cp_build_binary_op (location_t location,
else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
result_type = composite_pointer_type (type0, type1, op0, op1,
CPO_COMPARISON, complain);
- else if (code0 == POINTER_TYPE && null_ptr_cst_p (op1))
+ else if (code0 == POINTER_TYPE && null_ptr_cst_p (orig_op1))
{
result_type = type0;
if (extra_warnings && (complain & tf_warning))
warning (OPT_Wextra,
"ordered comparison of pointer with integer zero");
}
- else if (code1 == POINTER_TYPE && null_ptr_cst_p (op0))
+ else if (code1 == POINTER_TYPE && null_ptr_cst_p (orig_op0))
{
result_type = type1;
if (extra_warnings && (complain & tf_warning))
warning (OPT_Wextra,
"ordered comparison of pointer with integer zero");
}
- else if (null_ptr_cst_p (op0) && null_ptr_cst_p (op1))
+ else if (null_ptr_cst_p (orig_op0) && null_ptr_cst_p (orig_op1))
/* One of the operands must be of nullptr_t type. */
result_type = TREE_TYPE (nullptr_node);
else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
diff --git gcc/testsuite/g++.dg/cpp0x/nullptr37.C
gcc/testsuite/g++.dg/cpp0x/nullptr37.C
index e69de29..e746a28 100644
--- gcc/testsuite/g++.dg/cpp0x/nullptr37.C
+++ gcc/testsuite/g++.dg/cpp0x/nullptr37.C
@@ -0,0 +1,78 @@
+/* PR c++/64767 */
+// { dg-do compile { target c++11 } }
+
+int
+f1 (int *p, int **q)
+{
+ int r = 0;
+
+ r += p == '\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += p == L'\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += p == u'\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += p == U'\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += p != '\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += p != L'\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += p != u'\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += p != U'\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+
+ r += '\0' == p; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += L'\0' == p; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += u'\0' == p; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += U'\0' == p; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += '\0' != p; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += L'\0' != p; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += u'\0' != p; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += U'\0' != p; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+
+ r += q == '\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += q == L'\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += q == u'\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += q == U'\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += q != '\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += q != L'\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += q != u'\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += q != U'\0'; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+
+ r += '\0' == q; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += L'\0' == q; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += u'\0' == q; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += U'\0' == q; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += '\0' != q; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += L'\0' != q; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += u'\0' != q; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += U'\0' != q; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+
+ return r;
+}
+
+int
+f2 (int *p)
+{
+ int r = 0;
+
+ r += p == (void *) 0;
+ r += p != (void *) 0;
+ r += (void *) 0 == p;
+ r += (void *) 0 != p;
+
+ r += p == 0;
+ r += p != 0;
+ r += 0 == p;
+ r += 0 != p;
+
+ return r;
+}
+
+int
+f3 (int *p)
+{
+ int r = 0;
+
+ r += p == (char) 0; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += p != (char) 0; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+
+ r += (char) 0 == p; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+ r += (char) 0 != p; // { dg-error "ISO C\\+\\+ forbids comparison between
pointer and integer" }
+
+ return r;
+}
Marek
