[C++ PATCH] ctor vtable vcall offsets
Nathan Sidwell
nathan@codesourcery.com
Tue Feb 27 05:40:00 GMT 2001
Hi,
I've installed the attached patch to both the mainline and 3.0 branch.
We were not generating correct constructor vtable vcall offsets for
class heirarchies with nearly-empty primary virtual bases. If you
called a virtual function in a ctor/dtor that had been overridden from a
virtual base, bad things might have happened, now they don't.
built & tested on i686-pc-linux-gnu, approved by Mark.
nathan
--
Dr Nathan Sidwell :: http://www.codesourcery.com :: CodeSourcery LLC
'But that's a lie.' - 'Yes it is. What's your point?'
nathan@codesourcery.com : http://www.cs.bris.ac.uk/~nathan/ : nathan@acm.org
2001-02-27 Nathan Sidwell <nathan@codesourcery.com>
Fix ctor vtable vcall offsets.
* class.c (struct vtbl_init_data_s): Add rtti_binfo member.
(build_rtt_vtbl_entries): Lose RTTI_BINFO parameter.
(get_matching_base): Remove.
(get_original_base): New function.
(build_vtbl_initializer): Initialize vid.rtti_binfo.
Use a virtual thunk for a ctor vtable with an index
(add_vcall_offset_vtbl_entries_1): Check if binfo has lost a
primary base within a constructor vtable. Only set
BV_VCALL_INDEX when not a constructor vtable. Adjust vcall offset
when primary base has been lost.
* cp-tree.h (BINFO_VIRTUALS): Remove ambiguity from comment.
2001-02-27 Nathan Sidwell <nathan@codesourcery.com>
* g++.old-deja/g++.abi/vtable3.h: Check vcall offsets too.
Index: cp/class.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/cp/class.c,v
retrieving revision 1.364
diff -c -3 -p -r1.364 class.c
*** class.c 2001/02/21 14:42:23 1.364
--- class.c 2001/02/27 10:31:51
*************** typedef struct vtbl_init_data_s
*** 66,73 ****
{
/* The base for which we're building initializers. */
tree binfo;
! /* The binfo for the most-derived type. */
tree derived;
/* The negative-index vtable initializers built up so far. These
are in order from least negative index to most negative index. */
tree inits;
--- 66,76 ----
{
/* The base for which we're building initializers. */
tree binfo;
! /* The type of the most-derived type. */
tree derived;
+ /* The binfo for the dynamic type. This will be TYPE_BINFO (derived),
+ unless ctor_vtbl_p is true. */
+ tree rtti_binfo;
/* The negative-index vtable initializers built up so far. These
are in order from least negative index to most negative index. */
tree inits;
*************** static void accumulate_vtbl_inits PARAMS
*** 182,188 ****
static tree dfs_accumulate_vtbl_inits PARAMS ((tree, tree, tree, tree,
tree));
static void set_vindex PARAMS ((tree, int *));
! static void build_rtti_vtbl_entries PARAMS ((tree, tree, vtbl_init_data *));
static void build_vcall_and_vbase_vtbl_entries PARAMS ((tree,
vtbl_init_data *));
static void force_canonical_binfo_r PARAMS ((tree, tree, tree, tree));
--- 185,191 ----
static tree dfs_accumulate_vtbl_inits PARAMS ((tree, tree, tree, tree,
tree));
static void set_vindex PARAMS ((tree, int *));
! static void build_rtti_vtbl_entries PARAMS ((tree, vtbl_init_data *));
static void build_vcall_and_vbase_vtbl_entries PARAMS ((tree,
vtbl_init_data *));
static void force_canonical_binfo_r PARAMS ((tree, tree, tree, tree));
*************** static tree *build_vtt_inits PARAMS ((tr
*** 199,205 ****
static tree dfs_build_secondary_vptr_vtt_inits PARAMS ((tree, void *));
static tree dfs_ctor_vtable_bases_queue_p PARAMS ((tree, void *data));
static tree dfs_fixup_binfo_vtbls PARAMS ((tree, void *));
! static tree get_matching_base PARAMS ((tree, tree));
static tree dfs_get_primary_binfo PARAMS ((tree, void*));
static int record_subobject_offset PARAMS ((tree, tree, splay_tree));
static int check_subobject_offset PARAMS ((tree, tree, splay_tree));
--- 202,208 ----
static tree dfs_build_secondary_vptr_vtt_inits PARAMS ((tree, void *));
static tree dfs_ctor_vtable_bases_queue_p PARAMS ((tree, void *data));
static tree dfs_fixup_binfo_vtbls PARAMS ((tree, void *));
! static tree get_original_base PARAMS ((tree, tree));
static tree dfs_get_primary_binfo PARAMS ((tree, void*));
static int record_subobject_offset PARAMS ((tree, tree, splay_tree));
static int check_subobject_offset PARAMS ((tree, tree, splay_tree));
*************** build_vtt (t)
*** 6830,6861 ****
initialize_array (vtt, inits);
}
! /* The type corresponding to BINFO is a base class of T, but BINFO is
! in the base class hierarchy of a class derived from T. Return the
! base, in T's hierarchy, that corresponds to BINFO. */
static tree
! get_matching_base (binfo, t)
tree binfo;
- tree t;
{
tree derived;
! int i;
!
! if (same_type_p (BINFO_TYPE (binfo), t))
return binfo;
!
! if (TREE_VIA_VIRTUAL (binfo))
! return binfo_for_vbase (BINFO_TYPE (binfo), t);
!
! derived = get_matching_base (BINFO_INHERITANCE_CHAIN (binfo), t);
! for (i = 0; i < BINFO_N_BASETYPES (derived); ++i)
! if (same_type_p (BINFO_TYPE (BINFO_BASETYPE (derived, i)),
! BINFO_TYPE (binfo)))
! return BINFO_BASETYPE (derived, i);
!
! my_friendly_abort (20000628);
! return NULL_TREE;
}
/* Recursively build the VTT-initializer for BINFO (which is in the
--- 6833,6863 ----
initialize_array (vtt, inits);
}
! /* The type corresponding to BASE_BINFO is a base of the type of BINFO, but
! from within some heirarchy which is inherited from the type of BINFO.
! Return BASE_BINFO's equivalent binfo from the hierarchy dominated by
! BINFO. */
static tree
! get_original_base (base_binfo, binfo)
! tree base_binfo;
tree binfo;
{
tree derived;
! int ix;
!
! if (same_type_p (BINFO_TYPE (base_binfo), BINFO_TYPE (binfo)))
return binfo;
! if (TREE_VIA_VIRTUAL (base_binfo))
! return binfo_for_vbase (BINFO_TYPE (base_binfo), BINFO_TYPE (binfo));
! derived = get_original_base (BINFO_INHERITANCE_CHAIN (base_binfo), binfo);
!
! for (ix = 0; ix != BINFO_N_BASETYPES (derived); ix++)
! if (same_type_p (BINFO_TYPE (base_binfo),
! BINFO_TYPE (BINFO_BASETYPE (derived, ix))))
! return BINFO_BASETYPE (derived, ix);
! my_friendly_abort (20010223);
! return NULL;
}
/* Recursively build the VTT-initializer for BINFO (which is in the
*************** build_vtbl_initializer (binfo, orig_binf
*** 7347,7352 ****
--- 7349,7355 ----
memset (&vid, 0, sizeof (vid));
vid.binfo = binfo;
vid.derived = t;
+ vid.rtti_binfo = rtti_binfo;
vid.last_init = &vid.inits;
vid.primary_vtbl_p = (binfo == TYPE_BINFO (t));
vid.ctor_vtbl_p = !same_type_p (BINFO_TYPE (rtti_binfo), t);
*************** build_vtbl_initializer (binfo, orig_binf
*** 7354,7360 ****
vid.index = ssize_int (-3);
/* Add entries to the vtable for RTTI. */
! build_rtti_vtbl_entries (binfo, rtti_binfo, &vid);
/* Create an array for keeping track of the functions we've
processed. When we see multiple functions with the same
--- 7357,7363 ----
vid.index = ssize_int (-3);
/* Add entries to the vtable for RTTI. */
! build_rtti_vtbl_entries (binfo, &vid);
/* Create an array for keeping track of the functions we've
processed. When we see multiple functions with the same
*************** build_vtbl_initializer (binfo, orig_binf
*** 7384,7390 ****
tree fn;
tree pfn;
tree init;
!
/* Pull the offset for `this', and the function to call, out of
the list. */
delta = BV_DELTA (v);
--- 7387,7394 ----
tree fn;
tree pfn;
tree init;
! int generate_with_vtable_p = BV_GENERATE_THUNK_WITH_VTABLE_P (v);
!
/* Pull the offset for `this', and the function to call, out of
the list. */
delta = BV_DELTA (v);
*************** build_vtbl_initializer (binfo, orig_binf
*** 7394,7401 ****
vcall_index = BV_VCALL_INDEX (v);
my_friendly_assert (vcall_index != NULL_TREE, 20000621);
}
else
! vcall_index = NULL_TREE;
fn = BV_FN (v);
my_friendly_assert (TREE_CODE (delta) == INTEGER_CST, 19990727);
--- 7398,7414 ----
vcall_index = BV_VCALL_INDEX (v);
my_friendly_assert (vcall_index != NULL_TREE, 20000621);
}
+ else if (vid.ctor_vtbl_p && BV_VCALL_INDEX (v))
+ {
+ /* In the original, we did not need to use the vcall index, even
+ though there was one, but in a ctor vtable things might be
+ different (a primary virtual base might have moved). Be
+ conservative and use a vcall adjusting thunk. */
+ vcall_index = BV_VCALL_INDEX (v);
+ generate_with_vtable_p = 1;
+ }
else
! vcall_index = NULL_TREE;
fn = BV_FN (v);
my_friendly_assert (TREE_CODE (delta) == INTEGER_CST, 19990727);
*************** build_vtbl_initializer (binfo, orig_binf
*** 7413,7419 ****
TREE_CONSTANT (pfn) = 1;
/* Enter it in the vtable. */
init = build_vtable_entry (delta, vcall_index, pfn,
! BV_GENERATE_THUNK_WITH_VTABLE_P (v));
/* And add it to the chain of initializers. */
vfun_inits = tree_cons (NULL_TREE, init, vfun_inits);
}
--- 7426,7432 ----
TREE_CONSTANT (pfn) = 1;
/* Enter it in the vtable. */
init = build_vtable_entry (delta, vcall_index, pfn,
! generate_with_vtable_p);
/* And add it to the chain of initializers. */
vfun_inits = tree_cons (NULL_TREE, init, vfun_inits);
}
*************** add_vcall_offset_vtbl_entries_1 (binfo,
*** 7624,7629 ****
--- 7637,7643 ----
tree base_virtuals;
tree orig_virtuals;
tree binfo_inits;
+ int lost_primary = 0;
/* If BINFO is a primary base, this is the least derived class of
BINFO that is not a primary base. */
tree non_primary_binfo;
*************** add_vcall_offset_vtbl_entries_1 (binfo,
*** 7645,7650 ****
--- 7659,7679 ----
care about its vtable offsets. */
if (TREE_VIA_VIRTUAL (non_primary_binfo))
{
+ if (vid->ctor_vtbl_p)
+ {
+ tree probe;
+
+ for (probe = vid->binfo;
+ probe != non_primary_binfo;
+ probe = get_primary_binfo (probe))
+ {
+ if (BINFO_LOST_PRIMARY_P (probe))
+ {
+ lost_primary = 1;
+ break;
+ }
+ }
+ }
non_primary_binfo = vid->binfo;
break;
}
*************** add_vcall_offset_vtbl_entries_1 (binfo,
*** 7655,7660 ****
--- 7684,7695 ----
non_primary_binfo = b;
}
+ if (vid->ctor_vtbl_p)
+ /* For a ctor vtable we need the equivalent binfo within the hierarchy
+ where rtti_binfo is the most derived type. */
+ non_primary_binfo = get_original_base
+ (non_primary_binfo, TYPE_BINFO (BINFO_TYPE (vid->rtti_binfo)));
+
/* Make entries for the rest of the virtuals. */
for (base_virtuals = BINFO_VIRTUALS (binfo),
derived_virtuals = BINFO_VIRTUALS (non_primary_binfo),
*************** add_vcall_offset_vtbl_entries_1 (binfo,
*** 7669,7674 ****
--- 7704,7710 ----
tree base;
tree base_binfo;
size_t i;
+ tree vcall_offset;
/* Find the declaration that originally caused this function to
be present. */
*************** add_vcall_offset_vtbl_entries_1 (binfo,
*** 7699,7706 ****
|| (DECL_DESTRUCTOR_P (BV_FN (derived_entry))
&& DECL_DESTRUCTOR_P (fn)))
{
! BV_VCALL_INDEX (derived_virtuals)
! = BV_VCALL_INDEX (derived_entry);
break;
}
}
--- 7735,7743 ----
|| (DECL_DESTRUCTOR_P (BV_FN (derived_entry))
&& DECL_DESTRUCTOR_P (fn)))
{
! if (!vid->ctor_vtbl_p)
! BV_VCALL_INDEX (derived_virtuals)
! = BV_VCALL_INDEX (derived_entry);
break;
}
}
*************** add_vcall_offset_vtbl_entries_1 (binfo,
*** 7713,7724 ****
base_binfo = get_binfo (base, vid->derived, /*protect=*/0);
/* Compute the vcall offset. */
! *vid->last_init
! = (build_tree_list
! (NULL_TREE,
! fold (build1 (NOP_EXPR, vtable_entry_type,
! size_diffop (BINFO_OFFSET (base_binfo),
! BINFO_OFFSET (vid->vbase))))));
vid->last_init = &TREE_CHAIN (*vid->last_init);
/* Keep track of the vtable index where this vcall offset can be
--- 7750,7765 ----
base_binfo = get_binfo (base, vid->derived, /*protect=*/0);
/* Compute the vcall offset. */
! vcall_offset = BINFO_OFFSET (vid->vbase);
! if (lost_primary)
! vcall_offset = size_binop (PLUS_EXPR, vcall_offset,
! BINFO_OFFSET (vid->binfo));
! vcall_offset = size_diffop (BINFO_OFFSET (base_binfo),
! vcall_offset);
! vcall_offset = fold (build1 (NOP_EXPR, vtable_entry_type,
! vcall_offset));
!
! *vid->last_init = build_tree_list (NULL_TREE, vcall_offset);
vid->last_init = &TREE_CHAIN (*vid->last_init);
/* Keep track of the vtable index where this vcall offset can be
*************** add_vcall_offset_vtbl_entries_1 (binfo,
*** 7738,7749 ****
/* Return vtbl initializers for the RTTI entries coresponding to the
BINFO's vtable. The RTTI entries should indicate the object given
! by RTTI_BINFO. */
static void
! build_rtti_vtbl_entries (binfo, rtti_binfo, vid)
tree binfo;
- tree rtti_binfo;
vtbl_init_data *vid;
{
tree b;
--- 7779,7789 ----
/* Return vtbl initializers for the RTTI entries coresponding to the
BINFO's vtable. The RTTI entries should indicate the object given
! by VID->rtti_binfo. */
static void
! build_rtti_vtbl_entries (binfo, vid)
tree binfo;
vtbl_init_data *vid;
{
tree b;
*************** build_rtti_vtbl_entries (binfo, rtti_bin
*** 7754,7760 ****
tree init;
basetype = BINFO_TYPE (binfo);
! t = BINFO_TYPE (rtti_binfo);
/* For a COM object there is no RTTI entry. */
if (CLASSTYPE_COM_INTERFACE (basetype))
--- 7794,7800 ----
tree init;
basetype = BINFO_TYPE (binfo);
! t = BINFO_TYPE (vid->rtti_binfo);
/* For a COM object there is no RTTI entry. */
if (CLASSTYPE_COM_INTERFACE (basetype))
*************** build_rtti_vtbl_entries (binfo, rtti_bin
*** 7772,7778 ****
my_friendly_assert (BINFO_PRIMARY_BASE_OF (primary_base) == b, 20010127);
b = primary_base;
}
! offset = size_diffop (BINFO_OFFSET (rtti_binfo), BINFO_OFFSET (b));
/* The second entry is the address of the typeinfo object. */
if (flag_rtti)
--- 7812,7818 ----
my_friendly_assert (BINFO_PRIMARY_BASE_OF (primary_base) == b, 20010127);
b = primary_base;
}
! offset = size_diffop (BINFO_OFFSET (vid->rtti_binfo), BINFO_OFFSET (b));
/* The second entry is the address of the typeinfo object. */
if (flag_rtti)
*************** build_rtti_vtbl_entries (binfo, rtti_bin
*** 7802,7808 ****
/* Build an entry in the virtual function table. DELTA is the offset
for the `this' pointer. VCALL_INDEX is the vtable index containing
! the vcall offset; zero if none. ENTRY is the virtual function
table entry itself. It's TREE_TYPE must be VFUNC_PTR_TYPE_NODE,
but it may not actually be a virtual function table pointer. (For
example, it might be the address of the RTTI object, under the new
--- 7842,7848 ----
/* Build an entry in the virtual function table. DELTA is the offset
for the `this' pointer. VCALL_INDEX is the vtable index containing
! the vcall offset; NULL_TREE if none. ENTRY is the virtual function
table entry itself. It's TREE_TYPE must be VFUNC_PTR_TYPE_NODE,
but it may not actually be a virtual function table pointer. (For
example, it might be the address of the RTTI object, under the new
Index: cp/cp-tree.h
===================================================================
RCS file: /cvs/gcc/egcs/gcc/cp/cp-tree.h,v
retrieving revision 1.581
diff -c -3 -p -r1.581 cp-tree.h
*** cp-tree.h 2001/02/22 11:46:32 1.581
--- cp-tree.h 2001/02/27 10:31:54
*************** Boston, MA 02111-1307, USA. */
*** 136,142 ****
does not have a BV_FN; it is just an offset.
The BV_OVERRIDING_BASE is the binfo for the final overrider for
! this function. (This binfo's BINFO_TYPE will always be the same
as the DECL_CLASS_CONTEXT for the function.)
BINFO_VTABLE
--- 136,142 ----
does not have a BV_FN; it is just an offset.
The BV_OVERRIDING_BASE is the binfo for the final overrider for
! this function. (That binfo's BINFO_TYPE will always be the same
as the DECL_CLASS_CONTEXT for the function.)
BINFO_VTABLE
Index: testsuite/g++.old-deja/g++.abi/vtable3.h
===================================================================
RCS file: /cvs/gcc/egcs/gcc/testsuite/g++.old-deja/g++.abi/vtable3.h,v
retrieving revision 1.1
diff -c -3 -p -r1.1 vtable3.h
*** vtable3.h 2001/02/05 11:45:16 1.1
--- vtable3.h 2001/02/27 10:31:54
***************
*** 7,17 ****
#include <typeinfo>
#include <stdio.h>
- // XXX. vcall offsets are still broken, remove this define to re-enable
- // testing when fixed.
- #define NO_VCALL_TEST
-
int fail;
template <typename BASE, typename DERIVED>
int Test (DERIVED *d, int expect)
--- 7,14 ----
#include <typeinfo>
#include <stdio.h>
int fail;
+ struct A;
template <typename BASE, typename DERIVED>
int Test (DERIVED *d, int expect)
*************** int Test (DERIVED *d, int expect)
*** 19,24 ****
--- 16,22 ----
BASE *b = static_cast <BASE *> (d);
void *full_b = dynamic_cast <void *> (b);
void *full_d = dynamic_cast <void *> (d);
+ A *ap = static_cast <A *> (b);
if (full_b != full_d)
{
*************** int Test (DERIVED *d, int expect)
*** 37,44 ****
typeid (BASE).name (), typeid (DERIVED).name ());
return 1;
}
! #ifndef NO_VCALL_TEST
! b->Baz (static_cast <void *> (b));
int res = b->Foo (static_cast <void *> (d));
--- 35,42 ----
typeid (BASE).name (), typeid (DERIVED).name ());
return 1;
}
!
! b->Baz (static_cast <void *> (ap));
int res = b->Foo (static_cast <void *> (d));
*************** int Test (DERIVED *d, int expect)
*** 49,55 ****
typeid (BASE).name (), res, expect);
return 1;
}
! #endif
return 0;
}
--- 47,53 ----
typeid (BASE).name (), res, expect);
return 1;
}
!
return 0;
}
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