In two places when a struct demangle_component is of type DEMANGLE_COMPONENT_FIXED_TYPE we fall back to accessing the default s_binary member of the union rather than the s_fixed member. This is incorrect and can cause the demangler to crash.
In d_dump I've changed the code to only access the s_fixed member of the union, and also added printing of the remaining parts of the s_fixed struct, this felt like the most useful thing to do. I've added a new test, this causes a SIGSEGV for me before the patch, and is fine afterwords, however, this undefined, so might not cause a crash on all platforms. If this is approved then please could someone commit it for me, I don't have gcc write access. Thanks, Andrew libiberty/ChangeLog: * cp-demangle.c (d_dump): Only access field from s_fixed part of the union for DEMANGLE_COMPONENT_FIXED_TYPE. (d_count_templates_scopes): Likewise. * testsuite/demangle-expected: New test case. --- libiberty/cp-demangle.c | 10 +++++++++- libiberty/testsuite/demangle-expected | 6 ++++++ 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/libiberty/cp-demangle.c b/libiberty/cp-demangle.c index 68d8ee1..a31dad4 100644 --- a/libiberty/cp-demangle.c +++ b/libiberty/cp-demangle.c @@ -710,7 +710,9 @@ d_dump (struct demangle_component *dc, int indent) printf ("pointer to member type\n"); break; case DEMANGLE_COMPONENT_FIXED_TYPE: - printf ("fixed-point type\n"); + printf ("fixed-point type, accum? %d, sat? %d\n", + dc->u.s_fixed.accum, dc->u.s_fixed.sat); + d_dump (dc->u.s_fixed.length, indent + 2) break; case DEMANGLE_COMPONENT_ARGLIST: printf ("argument list\n"); @@ -3869,7 +3871,13 @@ d_count_templates_scopes (int *num_templates, int *num_scopes, case DEMANGLE_COMPONENT_FUNCTION_TYPE: case DEMANGLE_COMPONENT_ARRAY_TYPE: case DEMANGLE_COMPONENT_PTRMEM_TYPE: + goto recurse_left_right; + case DEMANGLE_COMPONENT_FIXED_TYPE: + d_count_templates_scopes (num_templates, num_scopes, + dc->u.s_fixed.length); + break; + case DEMANGLE_COMPONENT_VECTOR_TYPE: case DEMANGLE_COMPONENT_ARGLIST: case DEMANGLE_COMPONENT_TEMPLATE_ARGLIST: diff --git a/libiberty/testsuite/demangle-expected b/libiberty/testsuite/demangle-expected index 453f9a3..0e2bb12 100644 --- a/libiberty/testsuite/demangle-expected +++ b/libiberty/testsuite/demangle-expected @@ -4343,3 +4343,9 @@ cereal::detail::InputBindingMap<cereal::JSONInputArchive>::Serializers cereal::p --format=gnu-v3 _ZNSt9_Any_data9_M_accessIPZ4postISt8functionIFvvEEEvOT_EUlvE_EERS5_v void post<std::function<void ()> >(std::function<void ()>&&)::{lambda()#1}*& std::_Any_data::_M_access<void post<std::function<void ()> >(void post<std::function<void ()> >(std::function<void ()>&&)::{lambda()#1}*&&)::{lambda()#1}*>() +# The following input symbol was found during random, it caused a fault +# within the demangler, it's not a symbol we'd expect in the real world. +--format=auto --no-params +_Z3xxxDFyuVb +xxx(unsigned long long _Fract, bool volatile) +xxx -- 1.8.1.3