Fix incorrect parsing of arguments for nested functions

[arseny.kapoulkine]

Summary

For nested functions, local-name can be followed by function arguments; in
some cases the first argument starts with a digit (if it's a named type).

For example, this code:

void test() { struct g { void foo(Point p); }; }

Generates this name for symbol foo:

_ZZ4testvEN1g3fooE5Point

When decomposed, this results in a local-name with entity name N1g3fooE
(aka g::foo). According to Itanium ABI, entity name can be followed by
a discriminator that has to start with _.

However, libcxxabi defines an extension that says that discriminator can start
with a digit. This makes the grammar ambiguous, and causes 5 to be skipped and
Point to be parsed as a series of types for function arguments.

Resolve ambiguity by requiring that a digit-only discriminator is the last
token in the input string.

[arseny.kapoulkine]

Ping.

[mclow.lists]

This looks fine to me. Thanks for the patch (and the test case).

[mclow.lists]

landed as revision 249649

libcxxabi/trunk/src/cxa_demangle.cpp

if (first != last && *first == 'N')
         if (ends_with_template_args)
             *ends_with_template_args = component_ends_with_template_args;
     }
     return first;
 }
 
 // <discriminator> := _ <non-negative number>      # when number < 10
 //                 := __ <non-negative number> _   # when number >= 10
-//  extension      := decimal-digit+
+//  extension      := decimal-digit+               # at the end of string
 
 const char*
 parse_discriminator(const char* first, const char* last)
 {
     // parse but ignore discriminator
     if (first != last)
     {
         if (*first == '_')
if (first != last)
                 }
             }
         }
         else if (std::isdigit(*first))
         {
             const char* t1 = first+1;
             for (; t1 != last && std::isdigit(*t1); ++t1)
                 ;
-            first = t1;
+            if (t1 == last)
+                first = last;
         }
     }
     return first;
 }
 
 // <local-name> := Z <function encoding> E <entity name> [<discriminator>]
 //              := Z <function encoding> E s [<discriminator>]
 //              := Z <function encoding> Ed [ <parameter number> ] _ <entity name>

libcxxabi/trunk/test/test_demangle.pass.cpp

#endif
     {"_Z3fooPM2ABi", "foo(int AB::**)"},
     {"_Z1rM1GFivEMS_KFivES_M1HFivES1_4whatIKS_E5what2IS8_ES3_", "r(int (G::*)(), int (G::*)() const, G, int (H::*)(), int (G::*)(), what<G const>, what2<G const>, int (G::*)() const)"},
     {"_Z1fPU11objcproto1A11objc_object", "f(id<A>)"},
     {"_Z1fPKU11objcproto1A7NSArray", "f(NSArray<A> const*)"},
     {"_ZNK1AIJ1Z1Y1XEEcv1BIJDpPT_EEIJS2_S1_S0_EEEv", "A<Z, Y, X>::operator B<X*, Y*, Z*><X, Y, Z>() const"},
     {"_ZNK3Ncr6Silver7Utility6detail12CallOnThreadIZ53-[DeploymentSetupController handleManualServerEntry:]E3$_5EclIJEEEDTclclL_ZNS2_4getTIS4_EERT_vEEspclsr3stdE7forwardIT_Efp_EEEDpOSA_", "decltype(-[DeploymentSetupController handleManualServerEntry:]::$_5& Ncr::Silver::Utility::detail::getT<-[DeploymentSetupController handleManualServerEntry:]::$_5>()()(std::forward<-[DeploymentSetupController handleManualServerEntry:]::$_5>(fp))) Ncr::Silver::Utility::detail::CallOnThread<-[DeploymentSetupController handleManualServerEntry:]::$_5>::operator()<>(-[DeploymentSetupController handleManualServerEntry:]::$_5&&) const"},
     {"_Zli2_xy", "operator\"\" _x(unsigned long long)"},
     {"_Z1fIiEDcT_", "decltype(auto) f<int>(int)"},
+    {"_ZZ4testvEN1g3fooE5Point", "test()::g::foo(Point)"},
 };
 
 const unsigned N = sizeof(cases) / sizeof(cases[0]);
 
 const char* invalid_cases[] =
 {
     "_ZIPPreEncode",
     "Agentt",