[Bug demangler/70909] Libiberty Demangler segfaults (4)

["mark at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70909

--- Comment #50 from Mark Wielaard <mark at gcc dot gnu.org> ---
(In reply to Mark Wielaard from comment #49)
> (In reply to Pedro Alves from comment #48)
> > GDB is released separately from binutils though, and GDB 8.0 is going to
> > branch very soon.  IWBN to have this in the binutils-gdb repo by then.
> 
> Trying to integrate this into binutils-gdb produces a large number of
> unexpected failures in the gdb testsuite.

This is caused by gdb doing its own memory management to reuse
demangle_components. Whenever gdb d_grabs a new struct demangle_component we
now need to initialize d_printing to zero.

diff --git a/gdb/cp-name-parser.y b/gdb/cp-name-parser.y
index fd1e949..c997f20 100644
--- a/gdb/cp-name-parser.y
+++ b/gdb/cp-name-parser.y
@@ -190,6 +190,7 @@ fill_comp (enum demangle_component_type d_type, struct
demangle_component *lhs,
   struct demangle_component *ret = d_grab ();
   int i;

+  ret->d_printing = 0;
   i = cplus_demangle_fill_component (ret, d_type, lhs, rhs);
   gdb_assert (i);

@@ -201,6 +202,7 @@ make_empty (enum demangle_component_type d_type)
 {
   struct demangle_component *ret = d_grab ();
   ret->type = d_type;
+  ret->d_printing = 0;
   return ret;
 }

@@ -210,6 +212,7 @@ make_operator (const char *name, int args)
   struct demangle_component *ret = d_grab ();
   int i;

+  ret->d_printing = 0;
   i = cplus_demangle_fill_operator (ret, name, args);
   gdb_assert (i);

@@ -222,6 +225,7 @@ make_dtor (enum gnu_v3_dtor_kinds kind, struct
demangle_component *name)
   struct demangle_component *ret = d_grab ();
   int i;

+  ret->d_printing = 0;
   i = cplus_demangle_fill_dtor (ret, kind, name);
   gdb_assert (i);

@@ -234,6 +238,7 @@ make_builtin_type (const char *name)
   struct demangle_component *ret = d_grab ();
   int i;

+  ret->d_printing = 0;
   i = cplus_demangle_fill_builtin_type (ret, name);
   gdb_assert (i);

@@ -246,6 +251,7 @@ make_name (const char *name, int len)
   struct demangle_component *ret = d_grab ();
   int i;

+  ret->d_printing = 0;
   i = cplus_demangle_fill_name (ret, name, len);
   gdb_assert (i);


But maybe the cplus_demangle_fill_xxx functions should do this initializing
instead? In that case gdb only needs to handle initializing d_printing for its
own make_empty function.