The fix for bug 59195:
[C++ demangler handles conversion operator incorrectly]
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59195
unfortunately makes the demangler crash due to infinite recursion, in
case of casts in template parameters.
For example, with:
template<int> struct A {};
template <typename Y> void function_temp(A<sizeof ((Y)(999))>) {}
template void function_temp<int>(A<sizeof (int)>);
The 'function_temp<int>' instantiation above mangles to:
_Z13function_tempIiEv1AIXszcvT_Li999EEE
The demangler parses this as:
typed name
template
name 'function_temp'
template argument list
builtin type int
function type
builtin type void
argument list
template (*)
name 'A'
template argument list
unary operator
operator sizeof
unary operator
cast
template parameter 0 (**)
literal
builtin type int
name '999'
And after the fix for 59195, due to:
static void
d_print_cast (struct d_print_info *dpi, int options,
const struct demangle_component *dc)
{
...
/* For a cast operator, we need the template parameters from
the enclosing template in scope for processing the type. */
if (dpi->current_template != NULL)
{
dpt.next = dpi->templates;
dpi->templates = &dpt;
dpt.template_decl = dpi->current_template;
}
when printing the template argument list of A (what should be "<sizeof
(int)>"), the template parameter 0 (that is, "T_", the '**' above) now
refers to the first parameter of the the template argument list of the
'A' template (the '*' above), exactly what we were already trying to
print. This leads to infinite recursion, and stack exaustion. The
template parameter 0 should actually refer to the first parameter of
the 'function_temp' template.
Where it reads "for the cast operator" in the comment in d_print_cast
(above), it's really talking about a conversion operator, like:
struct A { template <typename U> explicit operator U(); };
We don't want to inject the template parameters from the enclosing
template in scope when processing a cast _expression_, only when
handling a conversion operator.
The problem is that DEMANGLE_COMPONENT_CAST is currently ambiguous,
and means _both_ 'conversion operator' and 'cast expression'.
Fix this by adding a new DEMANGLE_COMPONENT_CONVERSION component type,
which does what DEMANGLE_COMPONENT_CAST does today, and making
DEMANGLE_COMPONENT_CAST just simply print its component subtree.
I think we could instead reuse DEMANGLE_COMPONENT_CAST and in
d_print_comp_inner still do:
@@ -5001,9 +5013,9 @@ d_print_comp_inner (struct d_print_info *dpi, int options,
d_print_comp (dpi, options, dc->u.s_extended_operator.name);
return;
case DEMANGLE_COMPONENT_CAST:
d_append_string (dpi, "operator ");
- d_print_cast (dpi, options, dc);
+ d_print_conversion (dpi, options, dc);
return;
leaving the unary cast case below calling d_print_cast, but seems to
me that spliting the component types makes it easier to reason about
the code.
g++'s testsuite actually generates three symbols that crash the
demangler in the same way. I've added those as tests in the demangler
testsuite as well.
And then this fixes PR other/61233 too, which happens to be a
demangler crash originally reported to GDB, at:
https://sourceware.org/bugzilla/show_bug.cgi?id=16957
Bootstrapped and regtested on x86_64 Fedora 20.
Also ran this through GDB's testsuite. GDB will require a small
update to use DEMANGLE_COMPONENT_CONVERSION in one place it's using
DEMANGLE_COMPONENT_CAST in its sources.
libiberty/
2015-11-27 Pedro Alves <palves@redhat.com>
PR other/61321
PR other/61233
* demangle.h (enum demangle_component_type)
<DEMANGLE_COMPONENT_CONVERSION>: New value.
* cp-demangle.c (d_demangle_callback, d_make_comp): Handle
DEMANGLE_COMPONENT_CONVERSION.
(is_ctor_dtor_or_conversion): Handle DEMANGLE_COMPONENT_CONVERSION
instead of DEMANGLE_COMPONENT_CAST.
(d_operator_name): Return a DEMANGLE_COMPONENT_CONVERSION
component if handling a conversion.
(d_count_templates_scopes, d_print_comp_inner): Handle
DEMANGLE_COMPONENT_CONVERSION.
(d_print_comp_inner): Handle DEMANGLE_COMPONENT_CONVERSION instead
of DEMANGLE_COMPONENT_CAST.
(d_print_cast): Rename as ...
(d_print_conversion): ... this. Adjust comments.
(d_print_cast): Rewrite - simply print the left subcomponent.
* cp-demint.c (cplus_demangle_fill_component): Handle
DEMANGLE_COMPONENT_CONVERSION.
* testsuite/demangle-expected: Add tests.
From-SVN: r231020
921da19854