From 175ee55a229d9a02ae702f8818e2e022faae3132 Mon Sep 17 00:00:00 2001 From: Simon Marchi Date: Thu, 18 May 2023 15:05:56 -0400 Subject: [PATCH] gdbsupport: add support for references to checked_static_cast Add a checked_static_cast overload that works with references. A bad dynamic cast with references throws std::bad_cast, it would be possible to implement the new overload based on that, but it seemed simpler to just piggy back off the existing function. I found some potential uses of this new overload in amd-dbgapi-target.c, update them to illustrate the use of the new overload. To build amd-dbgapi-target.c, on needs the amd-dbgapi library, which I don't expect many people to have. But I have it, and it builds fine here. I did test the new overload by making a purposely bad cast and it did catch it. Change-Id: Id6b6a7db09fe3b4aa43cddb60575ff5f46761e96 Reviewed-By: Lancelot SIX Reviewed-By: Andrew Burgess --- gdb/amdgpu-tdep.c | 28 +++++++++++++++++++--------- gdbsupport/gdb-checked-static-cast.h | 16 ++++++++++++++++ 2 files changed, 35 insertions(+), 9 deletions(-) diff --git a/gdb/amdgpu-tdep.c b/gdb/amdgpu-tdep.c index 1077fab5c65..21a7a3ae1b7 100644 --- a/gdb/amdgpu-tdep.c +++ b/gdb/amdgpu-tdep.c @@ -674,7 +674,8 @@ amd_dbgapi_register_type_to_gdb_type (const amd_dbgapi_register_type &type, case amd_dbgapi_register_type::kind::INTEGER: { const auto &integer_type - = static_cast (type); + = gdb::checked_static_cast + (type); switch (integer_type.bit_size ()) { case 32: @@ -697,7 +698,8 @@ amd_dbgapi_register_type_to_gdb_type (const amd_dbgapi_register_type &type, case amd_dbgapi_register_type::kind::VECTOR: { const auto &vector_type - = static_cast (type); + = gdb::checked_static_cast + (type); struct type *element_type = amd_dbgapi_register_type_to_gdb_type (vector_type.element_type (), gdbarch); @@ -716,7 +718,8 @@ amd_dbgapi_register_type_to_gdb_type (const amd_dbgapi_register_type &type, case amd_dbgapi_register_type::kind::FLAGS: { const auto &flags_type - = static_cast (type); + = gdb::checked_static_cast + (type); struct type *gdb_type = arch_flags_type (gdbarch, flags_type.name ().c_str (), flags_type.bit_size ()); @@ -747,7 +750,8 @@ amd_dbgapi_register_type_to_gdb_type (const amd_dbgapi_register_type &type, case amd_dbgapi_register_type::kind::ENUM: { const auto &enum_type - = static_cast (type); + = gdb::checked_static_cast + (type); struct type *gdb_type = (type_allocator (gdbarch) .new_type (TYPE_CODE_ENUM, enum_type.bit_size (), @@ -1310,7 +1314,8 @@ amdgpu_register_type_parse_test () gdb_assert (type.kind () == amd_dbgapi_register_type::kind::FLAGS); - const auto &f = static_cast (type); + const auto &f + = gdb::checked_static_cast (type); gdb_assert (f.size () == 23); /* Check the two "FP_ROUND" fields. */ @@ -1322,7 +1327,8 @@ amdgpu_register_type_parse_test () == amd_dbgapi_register_type::kind::ENUM); const auto &e - = static_cast (*field.type); + = gdb::checked_static_cast + (*field.type); gdb_assert (e.size () == 4); gdb_assert (e[0].name == "NEAREST_EVEN"); gdb_assert (e[0].value == 0); @@ -1338,7 +1344,8 @@ amdgpu_register_type_parse_test () gdb_assert (f[22].type->kind () == amd_dbgapi_register_type::kind::INTEGER); const auto &i - = static_cast (*f[22].type); + = gdb::checked_static_cast + (*f[22].type); gdb_assert (i.bit_size () == 32); gdb_assert (i.is_unsigned ()); } @@ -1352,13 +1359,16 @@ amdgpu_register_type_parse_test () gdb_assert (type.kind () == amd_dbgapi_register_type::kind::VECTOR); - const auto &v = static_cast (type); + const auto &v + = gdb::checked_static_cast + (type); gdb_assert (v.count () == 64); const auto &et = v.element_type (); gdb_assert (et.kind () == amd_dbgapi_register_type::kind::INTEGER); - const auto &i = static_cast (et); + const auto &i + = gdb::checked_static_cast (et); gdb_assert (i.bit_size () == 32); gdb_assert (!i.is_unsigned ()); } diff --git a/gdbsupport/gdb-checked-static-cast.h b/gdbsupport/gdb-checked-static-cast.h index bc75244bddd..e9127b9c6e7 100644 --- a/gdbsupport/gdb-checked-static-cast.h +++ b/gdbsupport/gdb-checked-static-cast.h @@ -66,6 +66,22 @@ checked_static_cast (V *v) return result; } +/* Same as the above, but to cast from a reference type to another. */ + +template>> +T +checked_static_cast (V &v) +{ + static_assert (std::is_reference::value, "target must be a reference type"); + + using T_no_R = typename std::remove_reference::type; + using T_P = typename std::add_pointer::type; + + using V_no_R = typename std::remove_reference::type; + + return *checked_static_cast (&v); +} + } #endif /* COMMON_GDB_CHECKED_DYNAMIC_CAST_H */ -- 2.30.2