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Diffstat (limited to 'gdb/gnu-v3-abi.c')
| -rw-r--r-- | gdb/gnu-v3-abi.c | 434 |
1 files changed, 0 insertions, 434 deletions
diff --git a/gdb/gnu-v3-abi.c b/gdb/gnu-v3-abi.c deleted file mode 100644 index ae2104d59c4..00000000000 --- a/gdb/gnu-v3-abi.c +++ /dev/null @@ -1,434 +0,0 @@ -/* Abstraction of GNU v3 abi. - Contributed by Jim Blandy <jimb@redhat.com> - Copyright 2001 Free Software Foundation, Inc. - - This file is part of GDB. - - This program is free software; you can redistribute it and/or - modify it under the terms of the GNU General Public License as - published by the Free Software Foundation; either version 2 of the - License, or (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program; if not, write to the Free Software - Foundation, Inc., 59 Temple Place - Suite 330, - Boston, MA 02111-1307, USA. */ - -#include "defs.h" -#include "value.h" -#include "cp-abi.h" -#include "demangle.h" -#include "gdb_assert.h" - -static struct cp_abi_ops gnu_v3_abi_ops; - -static int -gnuv3_is_vtable_name (const char *name) -{ - return strncmp (name, "_ZTV", 4) == 0; -} - -static int -gnuv3_is_operator_name (const char *name) -{ - return strncmp (name, "operator", 8) == 0; -} - - -/* To help us find the components of a vtable, we build ourselves a - GDB type object representing the vtable structure. Following the - V3 ABI, it goes something like this: - - struct gdb_gnu_v3_abi_vtable { - - / * An array of virtual call and virtual base offsets. The real - length of this array depends on the class hierarchy; we use - negative subscripts to access the elements. Yucky, but - better than the alternatives. * / - ptrdiff_t vcall_and_vbase_offsets[0]; - - / * The offset from a virtual pointer referring to this table - to the top of the complete object. * / - ptrdiff_t offset_to_top; - - / * The type_info pointer for this class. This is really a - std::type_info *, but GDB doesn't really look at the - type_info object itself, so we don't bother to get the type - exactly right. * / - void *type_info; - - / * Virtual table pointers in objects point here. * / - - / * Virtual function pointers. Like the vcall/vbase array, the - real length of this table depends on the class hierarchy. * / - void (*virtual_functions[0]) (); - - }; - - The catch, of course, is that the exact layout of this table - depends on the ABI --- word size, endianness, alignment, etc. So - the GDB type object is actually a per-architecture kind of thing. - - vtable_type_gdbarch_data is a gdbarch per-architecture data pointer - which refers to the struct type * for this structure, laid out - appropriately for the architecture. */ -static struct gdbarch_data *vtable_type_gdbarch_data; - - -/* Human-readable names for the numbers of the fields above. */ -enum { - vtable_field_vcall_and_vbase_offsets, - vtable_field_offset_to_top, - vtable_field_type_info, - vtable_field_virtual_functions -}; - - -/* Return a GDB type representing `struct gdb_gnu_v3_abi_vtable', - described above, laid out appropriately for ARCH. - - We use this function as the gdbarch per-architecture data - initialization function. We assume that the gdbarch framework - calls the per-architecture data initialization functions after it - sets current_gdbarch to the new architecture. */ -static void * -build_gdb_vtable_type (struct gdbarch *arch) -{ - struct type *t; - struct field *field_list, *field; - int offset; - - struct type *void_ptr_type - = lookup_pointer_type (builtin_type_void); - struct type *ptr_to_void_fn_type - = lookup_pointer_type (lookup_function_type (builtin_type_void)); - - /* ARCH can't give us the true ptrdiff_t type, so we guess. */ - struct type *ptrdiff_type - = init_type (TYPE_CODE_INT, TARGET_PTR_BIT / TARGET_CHAR_BIT, 0, - "ptrdiff_t", 0); - - /* We assume no padding is necessary, since GDB doesn't know - anything about alignment at the moment. If this assumption bites - us, we should add a gdbarch method which, given a type, returns - the alignment that type requires, and then use that here. */ - - /* Build the field list. */ - field_list = xmalloc (sizeof (struct field [4])); - memset (field_list, 0, sizeof (struct field [4])); - field = &field_list[0]; - offset = 0; - - /* ptrdiff_t vcall_and_vbase_offsets[0]; */ - FIELD_NAME (*field) = "vcall_and_vbase_offsets"; - FIELD_TYPE (*field) - = create_array_type (0, ptrdiff_type, - create_range_type (0, builtin_type_int, 0, -1)); - FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT; - offset += TYPE_LENGTH (FIELD_TYPE (*field)); - field++; - - /* ptrdiff_t offset_to_top; */ - FIELD_NAME (*field) = "offset_to_top"; - FIELD_TYPE (*field) = ptrdiff_type; - FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT; - offset += TYPE_LENGTH (FIELD_TYPE (*field)); - field++; - - /* void *type_info; */ - FIELD_NAME (*field) = "type_info"; - FIELD_TYPE (*field) = void_ptr_type; - FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT; - offset += TYPE_LENGTH (FIELD_TYPE (*field)); - field++; - - /* void (*virtual_functions[0]) (); */ - FIELD_NAME (*field) = "virtual_functions"; - FIELD_TYPE (*field) - = create_array_type (0, ptr_to_void_fn_type, - create_range_type (0, builtin_type_int, 0, -1)); - FIELD_BITPOS (*field) = offset * TARGET_CHAR_BIT; - offset += TYPE_LENGTH (FIELD_TYPE (*field)); - field++; - - /* We assumed in the allocation above that there were four fields. */ - gdb_assert (field == (field_list + 4)); - - t = init_type (TYPE_CODE_STRUCT, offset, 0, 0, 0); - TYPE_NFIELDS (t) = field - field_list; - TYPE_FIELDS (t) = field_list; - TYPE_TAG_NAME (t) = "gdb_gnu_v3_abi_vtable"; - - return t; -} - - -/* Return the offset from the start of the imaginary `struct - gdb_gnu_v3_abi_vtable' object to the vtable's "address point" - (i.e., where objects' virtual table pointers point). */ -static int -vtable_address_point_offset () -{ - struct type *vtable_type = gdbarch_data (vtable_type_gdbarch_data); - - return (TYPE_FIELD_BITPOS (vtable_type, vtable_field_virtual_functions) - / TARGET_CHAR_BIT); -} - - -static struct type * -gnuv3_rtti_type (struct value *value, - int *full_p, int *top_p, int *using_enc_p) -{ - struct type *vtable_type = gdbarch_data (vtable_type_gdbarch_data); - struct type *value_type = check_typedef (VALUE_TYPE (value)); - CORE_ADDR vtable_address; - struct value *vtable; - struct minimal_symbol *vtable_symbol; - const char *vtable_symbol_name; - const char *class_name; - struct symbol *class_symbol; - struct type *run_time_type; - struct type *base_type; - LONGEST offset_to_top; - - /* We only have RTTI for class objects. */ - if (TYPE_CODE (value_type) != TYPE_CODE_CLASS) - return NULL; - - /* If we can't find the virtual table pointer for value_type, we - can't find the RTTI. */ - fill_in_vptr_fieldno (value_type); - if (TYPE_VPTR_FIELDNO (value_type) == -1) - return NULL; - - if (using_enc_p) - *using_enc_p = 0; - - /* Fetch VALUE's virtual table pointer, and tweak it to point at - an instance of our imaginary gdb_gnu_v3_abi_vtable structure. */ - base_type = check_typedef (TYPE_VPTR_BASETYPE (value_type)); - if (value_type != base_type) - { - value = value_cast (base_type, value); - if (using_enc_p) - *using_enc_p = 1; - } - vtable_address - = value_as_address (value_field (value, TYPE_VPTR_FIELDNO (value_type))); - vtable = value_at_lazy (vtable_type, - vtable_address - vtable_address_point_offset (), - VALUE_BFD_SECTION (value)); - - /* Find the linker symbol for this vtable. */ - vtable_symbol - = lookup_minimal_symbol_by_pc (VALUE_ADDRESS (vtable) - + VALUE_OFFSET (vtable) - + VALUE_EMBEDDED_OFFSET (vtable)); - if (! vtable_symbol) - return NULL; - - /* The symbol's demangled name should be something like "vtable for - CLASS", where CLASS is the name of the run-time type of VALUE. - If we didn't like this approach, we could instead look in the - type_info object itself to get the class name. But this way - should work just as well, and doesn't read target memory. */ - vtable_symbol_name = SYMBOL_DEMANGLED_NAME (vtable_symbol); - if (vtable_symbol_name == NULL - || strncmp (vtable_symbol_name, "vtable for ", 11)) - error ("can't find linker symbol for virtual table for `%s' value", - TYPE_NAME (value_type)); - class_name = vtable_symbol_name + 11; - - /* Try to look up the class name as a type name. */ - class_symbol = lookup_symbol (class_name, 0, STRUCT_NAMESPACE, 0, 0); - if (! class_symbol) - error ("can't find class named `%s', as given by C++ RTTI", class_name); - - /* Make sure the type symbol is sane. (An earlier version of this - code would find constructor functions, who have the same name as - the class.) */ - if (SYMBOL_CLASS (class_symbol) != LOC_TYPEDEF - || TYPE_CODE (SYMBOL_TYPE (class_symbol)) != TYPE_CODE_CLASS) - error ("C++ RTTI gives a class name of `%s', but that isn't a type name", - class_name); - - /* This is the object's run-time type! */ - run_time_type = SYMBOL_TYPE (class_symbol); - - /* Get the offset from VALUE to the top of the complete object. - NOTE: this is the reverse of the meaning of *TOP_P. */ - offset_to_top - = value_as_long (value_field (vtable, vtable_field_offset_to_top)); - - if (full_p) - *full_p = (- offset_to_top == VALUE_EMBEDDED_OFFSET (value) - && (TYPE_LENGTH (VALUE_ENCLOSING_TYPE (value)) - >= TYPE_LENGTH (run_time_type))); - if (top_p) - *top_p = - offset_to_top; - - return run_time_type; -} - - -static struct value * -gnuv3_virtual_fn_field (struct value **value_p, - struct fn_field *f, int j, - struct type *type, int offset) -{ - struct type *vtable_type = gdbarch_data (vtable_type_gdbarch_data); - struct value *value = *value_p; - struct type *value_type = check_typedef (VALUE_TYPE (value)); - struct type *vfn_base; - CORE_ADDR vtable_address; - struct value *vtable; - struct value *vfn; - - /* Some simple sanity checks. */ - if (TYPE_CODE (value_type) != TYPE_CODE_CLASS) - error ("Only classes can have virtual functions."); - - /* Find the base class that defines this virtual function. */ - vfn_base = TYPE_FN_FIELD_FCONTEXT (f, j); - if (! vfn_base) - /* In programs compiled with G++ version 1, the debug info doesn't - say which base class defined the virtual function. We'll guess - it's the same base class that has our vtable; this is wrong for - multiple inheritance, but it's better than nothing. */ - vfn_base = TYPE_VPTR_BASETYPE (type); - - /* This type may have been defined before its virtual function table - was. If so, fill in the virtual function table entry for the - type now. */ - if (TYPE_VPTR_FIELDNO (vfn_base) < 0) - fill_in_vptr_fieldno (vfn_base); - - /* Now that we know which base class is defining our virtual - function, cast our value to that baseclass. This takes care of - any necessary `this' adjustments. */ - if (vfn_base != value_type) - value = value_cast (vfn_base, value); - - /* Now value is an object of the appropriate base type. Fetch its - virtual table. */ - /* It might be possible to do this cast at the same time as the above. - Does multiple inheritance affect this? - Can this even trigger, or is TYPE_VPTR_BASETYPE idempotent? - */ - if (TYPE_VPTR_BASETYPE (vfn_base) != vfn_base) - value = value_cast (TYPE_VPTR_BASETYPE (vfn_base), value); - vtable_address - = value_as_address (value_field (value, TYPE_VPTR_FIELDNO (vfn_base))); - - vtable = value_at_lazy (vtable_type, - vtable_address - vtable_address_point_offset (), - VALUE_BFD_SECTION (value)); - - /* Fetch the appropriate function pointer from the vtable. */ - vfn = value_subscript (value_field (vtable, vtable_field_virtual_functions), - value_from_longest (builtin_type_int, - TYPE_FN_FIELD_VOFFSET (f, j))); - - /* Cast the function pointer to the appropriate type. */ - vfn = value_cast (lookup_pointer_type (TYPE_FN_FIELD_TYPE (f, j)), - vfn); - - /* Is (type)value always numerically the same as (vfn_base)value? - If so we can spare this cast and use one of the ones above. */ - *value_p = value_addr (value_cast (type, *value_p)); - - return vfn; -} - -/* Compute the offset of the baseclass which is - the INDEXth baseclass of class TYPE, - for value at VALADDR (in host) at ADDRESS (in target). - The result is the offset of the baseclass value relative - to (the address of)(ARG) + OFFSET. - - -1 is returned on error. */ -int -gnuv3_baseclass_offset (struct type *type, int index, char *valaddr, - CORE_ADDR address) -{ - struct type *vtable_type = gdbarch_data (vtable_type_gdbarch_data); - struct type *basetype = TYPE_BASECLASS (type, index); - struct value *full_object, *vbase_object, *orig_object; - struct value *vtable, *orig_typeinfo, *orig_base_info; - struct type *orig_type, *vbasetype; - struct value *offset_val, *vbase_array; - CORE_ADDR vtable_address; - long int cur_base_offset, base_offset; - int to_top; - int baseclasses, i; - - /* If it isn't a virtual base, this is easy. The offset is in the - type definition. */ - if (!BASETYPE_VIA_VIRTUAL (type, index)) - return TYPE_BASECLASS_BITPOS (type, index) / 8; - - /* To access a virtual base, we need to use the vbase offset stored in - our vtable. Recent GCC versions provide this information. If it isn't - available, we could get what we needed from RTTI, or from drawing the - complete inheritance graph based on the debug info. Neither is - worthwhile. */ - cur_base_offset = TYPE_BASECLASS_BITPOS (type, index) / 8; - if (cur_base_offset >= - vtable_address_point_offset ()) - error ("Expected a negative vbase offset (old compiler?)"); - - cur_base_offset = cur_base_offset + vtable_address_point_offset (); - if ((- cur_base_offset) % TYPE_LENGTH (builtin_type_void_data_ptr) != 0) - error ("Misaligned vbase offset."); - cur_base_offset = cur_base_offset - / ((int) TYPE_LENGTH (builtin_type_void_data_ptr)); - - /* We're now looking for the cur_base_offset'th entry (negative index) - in the vcall_and_vbase_offsets array. */ - - orig_object = value_at_lazy (type, address, NULL); - vbasetype = TYPE_VPTR_BASETYPE (VALUE_TYPE (orig_object)); - vbase_object = value_cast (vbasetype, orig_object); - - vtable_address - = value_as_address (value_field (vbase_object, - TYPE_VPTR_FIELDNO (vbasetype))); - vtable = value_at_lazy (vtable_type, - vtable_address - vtable_address_point_offset (), - NULL); - offset_val = value_from_longest(builtin_type_int, cur_base_offset); - vbase_array = value_field (vtable, vtable_field_vcall_and_vbase_offsets); - base_offset = value_as_long (value_subscript (vbase_array, offset_val)); - return base_offset; -} - -static void -init_gnuv3_ops (void) -{ - vtable_type_gdbarch_data = register_gdbarch_data (build_gdb_vtable_type, 0); - - gnu_v3_abi_ops.shortname = "gnu-v3"; - gnu_v3_abi_ops.longname = "GNU G++ Version 3 ABI"; - gnu_v3_abi_ops.doc = "G++ Version 3 ABI"; - gnu_v3_abi_ops.is_destructor_name = is_gnu_v3_mangled_dtor; - gnu_v3_abi_ops.is_constructor_name = is_gnu_v3_mangled_ctor; - gnu_v3_abi_ops.is_vtable_name = gnuv3_is_vtable_name; - gnu_v3_abi_ops.is_operator_name = gnuv3_is_operator_name; - gnu_v3_abi_ops.rtti_type = gnuv3_rtti_type; - gnu_v3_abi_ops.virtual_fn_field = gnuv3_virtual_fn_field; - gnu_v3_abi_ops.baseclass_offset = gnuv3_baseclass_offset; -} - - -void -_initialize_gnu_v3_abi (void) -{ - init_gnuv3_ops (); - - register_cp_abi (gnu_v3_abi_ops); -} |