Re: [PATCH][PR91979] Incorrect mangling for non-template-argument nullptr expression

[kamlesh kumar <kamleshbhalui@gmail.com>]

diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index a9333b8..334610c 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -3400,7 +3400,8 @@ write_template_arg_literal (const tree value)
       case INTEGER_CST:
        gcc_assert (!same_type_p (TREE_TYPE (value), boolean_type_node)
                    || integer_zerop (value) || integer_onep (value));
-       write_integer_cst (value);
+       if (!NULLPTR_TYPE_P (TREE_TYPE (value)))
+         write_integer_cst (value);
        break;

       case REAL_CST:
diff --git a/gcc/testsuite/g++.dg/cpp0x/nullptr27.C
b/gcc/testsuite/g++.dg/cpp0x/nullptr27.C
index 2510dc8..edd1160 100644
--- a/gcc/testsuite/g++.dg/cpp0x/nullptr27.C
+++ b/gcc/testsuite/g++.dg/cpp0x/nullptr27.C
@@ -1,7 +1,7 @@
 // PR c++/52706
 // { dg-do compile { target c++11 } }
 // { dg-options "-fabi-version=0" }
-// { dg-final { scan-assembler "_Z1fIDnLDn0EEiT_" } }
+// { dg-final { scan-assembler "_Z1fIDnLDnEEiT_" } }

 template<class T, decltype(nullptr) = nullptr>
 int f(T);
diff --git a/gcc/testsuite/g++.dg/cpp0x/pr91979.C
b/gcc/testsuite/g++.dg/cpp0x/pr91979.C
new file mode 100644
index 0000000..7fcd56b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/pr91979.C
@@ -0,0 +1,15 @@
+// PR c++/91989
+// { dg-do compile { target c++11 } }
+// { dg-final { scan-assembler
"_Z3fooILPv0EEvPN9enable_ifIXeqT_LDnEEvE4typeE" } }
+
+template <bool, typename T = void>
+struct enable_if {};
+
+template <typename T>
+struct enable_if<true, T> { typedef T type; };
+
+template <void *P>
+void foo(typename enable_if<P == nullptr>::type* = 0) {}
+
+template void foo<(void *)0>(void *);
+
diff --git a/libiberty/cp-demangle.c b/libiberty/cp-demangle.c
index aa78c86..3c32b26 100644
--- a/libiberty/cp-demangle.c
+++ b/libiberty/cp-demangle.c
@@ -3577,6 +3577,16 @@ d_expr_primary (struct d_info *di)
          && type->u.s_builtin.type->print != D_PRINT_DEFAULT)
        di->expansion -= type->u.s_builtin.type->len;

+      if (type->type == DEMANGLE_COMPONENT_BUILTIN_TYPE
+          &&
strncmp(type->u.s_builtin.type->name,cplus_demangle_builtin_types[33].name,17)
== 0)
+        {
+          if (d_peek_char (di) == 'E')
+            {
+              d_advance (di, 1);
+              return type;
+            }
+        }
+
       /* Rather than try to interpret the literal value, we just
         collect it as a string.  Note that it's possible to have a
         floating point literal here.  The ABI specifies that the
diff --git a/libiberty/testsuite/demangle-expected
b/libiberty/testsuite/demangle-expected
index f21ed00..b23a7c2 100644
--- a/libiberty/testsuite/demangle-expected
+++ b/libiberty/testsuite/demangle-expected
@@ -1446,3 +1446,7 @@ Foo<int>()::X::fn
 _ZZZ3FooIiEfvENKUlT_E_clIcEEDaS0_EN1X2fnEv
 Foo<int>()::{lambda(auto:1)#1}::operator()<char>(char) const::X::fn()
 Foo<int>()::{lambda(auto:1)#1}::operator()<char>(char) const::X::fn
+#PR91979 demangling nullptr expression
+
+_Z3fooILPv0EEvPN9enable_ifIXeqT_LDnEEvE4typeE
+void foo<(void*)0>(enable_if<((void*)0)==((decltype(nullptr))),
void>::type*)

On Tue, Oct 22, 2019 at 10:50 PM kamlesh kumar <kamleshbhalui@gmail.com>
wrote:

> Marek,
> updated the patch as per your suggestion.
> Regarding -fabi-version.
> this is what Jonathan said:
>
> This might need a new -fabi-version to preserve the old mangling for compatibility, but I'll let Jason determine that.
>
>
> Thanks.
>
>
>
> On Tue, Oct 22, 2019 at 10:24 PM Marek Polacek <polacek@redhat.com> wrote:
>
>> On Tue, Oct 22, 2019 at 10:00:19PM +0530, kamlesh kumar wrote:
>> > diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
>> > index a9333b8..780da9f 100644
>> > --- a/gcc/cp/mangle.c
>> > +++ b/gcc/cp/mangle.c
>> > @@ -3400,7 +3400,8 @@ write_template_arg_literal (const tree value)
>> >        case INTEGER_CST:
>> >         gcc_assert (!same_type_p (TREE_TYPE (value), boolean_type_node)
>> >                     || integer_zerop (value) || integer_onep (value));
>> > -       write_integer_cst (value);
>> > +       if (TREE_CODE(TREE_TYPE(value)) != NULLPTR_TYPE)
>> > +         write_integer_cst (value);
>>
>> Please use NULLPTR_TYPE_P.
>>
>> Does this warrant a new -fabi-version?
>>
>> Marek
>>
>>