[Bug other/61321] New: demangler crash on casts in template parameters

[Bug other/61321] New: demangler crash on casts in template parameters

[palves at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

            Bug ID: 61321
           Summary: demangler crash on casts in template parameters
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: palves at redhat dot com

The fix for bug 59195 (C++ demangler handles conversion operator incorrectly)
makes the demangler crash crash due to infinite recursion, in case of casts in
template parameters.  For example:

 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  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 this patch, when printing the template argument list of A (what
should be "<sizeof (int)>"), the template parameter 0 (that is, "T_") now
refers to the first parameter of the the template argument list of the 'A'
template, exactly what we were trying to print, while it should actually refer
to the first parameter of the 'function_temp' template.  This leads to infinite
recursion, and stack exaustion.

(This is particularly nasty for GDB, as it causes an immediate crash at
startup.)

[Bug other/61321] demangler crash on casts in template parameters

[palves at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

--- Comment #1 from Pedro Alves <palves at redhat dot com> ---
I think we need to distinguish conversion operators from expression casts.  

Working on a patch that adds:

--- c/include/demangle.h
+++ w/include/demangle.h
@@ -373,6 +373,10 @@ enum demangle_component_type
   /* A typecast, represented as a unary operator.  The one subtree is
      the type to which the argument should be cast.  */
   DEMANGLE_COMPONENT_CAST,
+  /* A conversion operator, represented as a unary operator.  The one
+     subtree is the type to which the argument should be converted
+     to.  */
+  DEMANGLE_COMPONENT_CONVERSION,

[Bug other/61321] demangler crash on casts in template parameters

[palves at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

--- Comment #2 from Pedro Alves <palves at redhat dot com> ---
That worked.  Running bootstrap/tests.

[Bug other/61321] demangler crash on casts in template parameters

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2014-05-26
           Assignee|unassigned at gcc dot gnu.org      |palves at redhat dot com
     Ever confirmed|0                           |1

[Bug other/61321] demangler crash on casts in template parameters

[palves at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

--- Comment #3 from Pedro Alves <palves at redhat dot com> ---
https://gcc.gnu.org/ml/gcc-patches/2014-05/msg02279.html

[Bug other/61321] demangler crash on casts in template parameters

[ccoutant at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

Cary Coutant <ccoutant at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |riku at multitaction dot com

--- Comment #4 from Cary Coutant <ccoutant at gcc dot gnu.org> ---
*** Bug 63425 has been marked as a duplicate of this bug. ***

[Bug other/61321] demangler crash on casts in template parameters

[ccoutant at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

Cary Coutant <ccoutant at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |nheghathivhistha at gmail dot com

--- Comment #5 from Cary Coutant <ccoutant at gcc dot gnu.org> ---
*** Bug 63244 has been marked as a duplicate of this bug. ***

[Bug other/61321] demangler crash on casts in template parameters

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

Markus Trippelsdorf <trippels at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |trippels at gcc dot gnu.org

--- Comment #6 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
*** Bug 65732 has been marked as a duplicate of this bug. ***

[Bug other/61321] demangler crash on casts in template parameters

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

--- Comment #7 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
Pedro could you please ping your patch?

[Bug other/61321] demangler crash on casts in template parameters

[palves at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

--- Comment #8 from Pedro Alves <palves at redhat dot com> ---
The patch was meanwhile approved:

 https://gcc.gnu.org/ml/gcc-patches/2014-11/msg01247.html

I'm afraid I won't have time to get back to this for at least a few weeks.
If someone else could push it, I'd appreciated it.

[Bug other/61321] demangler crash on casts in template parameters

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

--- Comment #9 from Markus Trippelsdorf <trippels at gcc dot gnu.org> ---
*** Bug 63465 has been marked as a duplicate of this bug. ***

[Bug other/61321] demangler crash on casts in template parameters

[miyuki at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61321

Mikhail Maltsev <miyuki at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |ian at airs dot com

--- Comment #10 from Mikhail Maltsev <miyuki at gcc dot gnu.org> ---
*** Bug 67261 has been marked as a duplicate of this bug. ***