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Convert gnu-v3-abi.c to new hash table

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This converts gnu-v3-abi.c to use the new hash table.

This change shows how a std::vector can easily be made directly from
the hash table, simplifying the earlier approach of constructing a
vector and a hash table at the same time.

Change-Id: Ia0c387a035a52300db6b6f5a3a2e5c69efa01155
Co-Authored-By: Tom Tromey <tom@tromey.com>
Approved-By: Tom Tromey <tom@tromey.com>
This commit is contained in:
Simon Marchi 2024-11-04 13:27:47 -05:00 committed by Simon Marchi
parent 9f33419814
commit 41c2bfb82f
1 changed files with 32 additions and 66 deletions
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98
gdb/gnu-v3-abi.c
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@ -33,6 +33,7 @@
#include "cli/cli-style.h"
#include "dwarf2/loc.h"
#include "inferior.h"
#include "gdbsupport/unordered_map.h"
static struct cp_abi_ops gnu_v3_abi_ops;
@ -791,51 +792,32 @@ gnuv3_method_ptr_to_value (struct value **this_p, struct value *method_ptr)
return value_from_pointer (lookup_pointer_type (method_type), ptr_value);
}
/* Objects of this type are stored in a hash table and a vector when
printing the vtables for a class. */
struct value_and_voffset
struct vtable_value_hash_t
{
/* The value representing the object. */
struct value *value;
/* The maximum vtable offset we've found for any object at this
offset in the outermost object. */
int max_voffset;
std::size_t operator() (value *val) const noexcept
{ return val->address () + val->embedded_offset (); }
};
/* Hash function for value_and_voffset. */
static hashval_t
hash_value_and_voffset (const void *p)
struct vtable_value_eq_t
{
const struct value_and_voffset *o = (const struct value_and_voffset *) p;
bool operator() (value *lhs, value *rhs) const noexcept
{
return (lhs->address () + lhs->embedded_offset ()
== rhs->address () + rhs->embedded_offset ());
}
};
return o->value->address () + o->value->embedded_offset ();
}
using vtable_hash_t
= gdb::unordered_map<value *, int, vtable_value_hash_t, vtable_value_eq_t>;
/* Equality function for value_and_voffset. */
static int
eq_value_and_voffset (const void *a, const void *b)
{
const struct value_and_voffset *ova = (const struct value_and_voffset *) a;
const struct value_and_voffset *ovb = (const struct value_and_voffset *) b;
return (ova->value->address () + ova->value->embedded_offset ()
== ovb->value->address () + ovb->value->embedded_offset ());
}
/* Comparison function for value_and_voffset. */
/* Comparison function used for sorting the vtable entries. */
static bool
compare_value_and_voffset (const struct value_and_voffset *va,
const struct value_and_voffset *vb)
compare_value_and_voffset (const std::pair<value *, int> &va,
const std::pair<value *, int> &vb)
{
CORE_ADDR addra = (va->value->address ()
+ va->value->embedded_offset ());
CORE_ADDR addrb = (vb->value->address ()
+ vb->value->embedded_offset ());
CORE_ADDR addra = va.first->address () + va.first->embedded_offset ();
CORE_ADDR addrb = vb.first->address () + vb.first->embedded_offset ();
return addra < addrb;
}
@ -843,18 +825,14 @@ compare_value_and_voffset (const struct value_and_voffset *va,
/* A helper function used when printing vtables. This determines the
key (most derived) sub-object at each address and also computes the
maximum vtable offset seen for the corresponding vtable. Updates
OFFSET_HASH and OFFSET_VEC with a new value_and_voffset object, if
needed. VALUE is the object to examine. */
OFFSET_HASH with a new value_and_voffset object, if needed. VALUE
is the object to examine. */
static void
compute_vtable_size (htab_t offset_hash,
std::vector<value_and_voffset *> *offset_vec,
struct value *value)
compute_vtable_size (vtable_hash_t &offset_hash, struct value *value)
{
int i;
struct type *type = check_typedef (value->type ());
void **slot;
struct value_and_voffset search_vo, *current_vo;
gdb_assert (type->code () == TYPE_CODE_STRUCT);
@ -864,18 +842,7 @@ compute_vtable_size (htab_t offset_hash,
return;
/* Update the hash and the vec, if needed. */
search_vo.value = value;
slot = htab_find_slot (offset_hash, &search_vo, INSERT);
if (*slot)
current_vo = (struct value_and_voffset *) *slot;
else
{
current_vo = XNEW (struct value_and_voffset);
current_vo->value = value;
current_vo->max_voffset = -1;
*slot = current_vo;
offset_vec->push_back (current_vo);
}
int &current_max_voffset = offset_hash.emplace (value, -1).first->second;
/* Update the value_and_voffset object with the highest vtable
offset from this class. */
@ -890,15 +857,15 @@ compute_vtable_size (htab_t offset_hash,
{
int voffset = TYPE_FN_FIELD_VOFFSET (fn, j);
if (voffset > current_vo->max_voffset)
current_vo->max_voffset = voffset;
if (voffset > current_max_voffset)
current_max_voffset = voffset;
}
}
}
/* Recurse into base classes. */
for (i = 0; i < TYPE_N_BASECLASSES (type); ++i)
compute_vtable_size (offset_hash, offset_vec, value_field (value, i));
compute_vtable_size (offset_hash, value_field (value, i));
}
/* Helper for gnuv3_print_vtable that prints a single vtable. */
@ -999,23 +966,22 @@ gnuv3_print_vtable (struct value *value)
return;
}
htab_up offset_hash (htab_create_alloc (1, hash_value_and_voffset,
eq_value_and_voffset,
xfree, xcalloc, xfree));
std::vector<value_and_voffset *> result_vec;
vtable_hash_t offset_hash;
compute_vtable_size (offset_hash, value);
compute_vtable_size (offset_hash.get (), &result_vec, value);
std::vector<std::pair<struct value *, int>> result_vec (offset_hash.begin (),
offset_hash.end ());
std::sort (result_vec.begin (), result_vec.end (),
compare_value_and_voffset);
count = 0;
for (value_and_voffset *iter : result_vec)
for (auto &item : result_vec)
{
if (iter->max_voffset >= 0)
if (item.second >= 0)
{
if (count > 0)
gdb_printf ("\n");
print_one_vtable (gdbarch, iter->value, iter->max_voffset, &opts);
print_one_vtable (gdbarch, item.first, item.second, &opts);
++count;
}
}