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.
Curiously, nothing in the testsuite broke.
Bootstrapped/regtested on x86_64-linux and ppc64-linux, ok for trunk?
2016-09-30 Marek Polacek <pola...@redhat.com>
Core 903
* typeck.c (cp_build_binary_op) [EQ_EXPR]: Diagnose invalid pointer
conversions.
* g++.dg/cpp0x/nullptr37.C: New test.
diff --git gcc/cp/typeck.c gcc/cp/typeck.c
index 617ca55..2e6f44e 100644
--- gcc/cp/typeck.c
+++ gcc/cp/typeck.c
@@ -4584,6 +4584,14 @@ cp_build_binary_op (location_t location,
else
result_type = type0;
+ if (null_ptr_cst_p (op1) && !null_ptr_cst_p (orig_op1))
+ {
+ if (complain & tf_error)
+ permerror (input_location, "ISO C++11 only allows pointer "
+ "conversions for integer literals");
+ else
+ return error_mark_node;
+ }
warn_for_null_address (location, op0, complain);
}
else if (((code1 == POINTER_TYPE || TYPE_PTRDATAMEM_P (type1))
@@ -4598,6 +4606,14 @@ cp_build_binary_op (location_t location,
else
result_type = type1;
+ if (null_ptr_cst_p (op0) && !null_ptr_cst_p (orig_op0))
+ {
+ if (complain & tf_error)
+ permerror (input_location, "ISO C++11 only allows pointer "
+ "conversions for integer literals");
+ else
+ return error_mark_node;
+ }
warn_for_null_address (location, op1, complain);
}
else if ((code0 == POINTER_TYPE && code1 == POINTER_TYPE)
diff --git gcc/testsuite/g++.dg/cpp0x/nullptr37.C
gcc/testsuite/g++.dg/cpp0x/nullptr37.C
index e69de29..17c33d1 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\\+\\+11 only allows pointer conversions
for integer literals" } */
+ r += p == L'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += p == u'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += p == U'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += p != '\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions
for integer literals" } */
+ r += p != L'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += p != u'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += p != U'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+
+ r += '\0' == p; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions
for integer literals" } */
+ r += L'\0' == p; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += u'\0' == p; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += U'\0' == p; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += '\0' != p; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions
for integer literals" } */
+ r += L'\0' != p; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += u'\0' != p; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += U'\0' != p; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+
+ r += q == '\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions
for integer literals" } */
+ r += q == L'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += q == u'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += q == U'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += q != '\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions
for integer literals" } */
+ r += q != L'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += q != u'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += q != U'\0'; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+
+ r += '\0' == q; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions
for integer literals" } */
+ r += L'\0' == q; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += u'\0' == q; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += U'\0' == q; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += '\0' != q; /* { dg-error "ISO C\\+\\+11 only allows pointer conversions
for integer literals" } */
+ r += L'\0' != q; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += u'\0' != q; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += U'\0' != q; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+
+ 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\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += p != (char) 0; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+
+ r += (char) 0 == p; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+ r += (char) 0 != p; /* { dg-error "ISO C\\+\\+11 only allows pointer
conversions for integer literals" } */
+
+ return r;
+}
Marek
