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Fix the BFD library's parsing of DIEs where specification attributes can refer to variables that are defined later on.

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PR 27484
	* dwarf2.c (scan_unit_for_symbols): Scan twice, once to accumulate
	function and variable tags and a second time to resolve their
	attributes.
This commit is contained in:
Nick Clifton 2021-03-02 16:08:23 +00:00
parent 211bcd0133
commit ca8f6bc629
2 changed files with 114 additions and 26 deletions
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7
bfd/ChangeLog
View file

@ -1,3 +1,10 @@
2021-03-02 Nick Clifton <nickc@redhat.com>
PR 27484
* dwarf2.c (scan_unit_for_symbols): Scan twice, once to accumulate
function and variable tags and a second time to resolve their
attributes.
2021-03-02 Nick Alcock <nick.alcock@oracle.com>
* elf-strtab.c (_bfd_elf_strtab_str): Skip strings with zero refcount.

133
bfd/dwarf2.c
View file

@ -1484,6 +1484,8 @@ struct funcinfo
struct arange arange;
/* Where the symbol is defined. */
asection * sec;
/* The offset of the funcinfo from the start of the unit. */
bfd_uint64_t unit_offset;
};
struct lookup_funcinfo
@ -3304,6 +3306,15 @@ read_rangelist (struct comp_unit *unit, struct arange *arange,
return read_rnglists (unit, arange, offset);
}
static struct funcinfo *
lookup_func_by_offset (bfd_uint64_t offset, struct funcinfo * table)
{
for (; table != NULL; table = table->prev_func)
if (table->unit_offset == offset)
return table;
return NULL;
}
static struct varinfo *
lookup_var_by_offset (bfd_uint64_t offset, struct varinfo * table)
{
@ -3330,7 +3341,8 @@ scan_unit_for_symbols (struct comp_unit *unit)
bfd_byte *info_ptr = unit->first_child_die_ptr;
bfd_byte *info_ptr_end = unit->end_ptr;
int nesting_level = 0;
struct nest_funcinfo {
struct nest_funcinfo
{
struct funcinfo *func;
} *nested_funcs;
int nested_funcs_size;
@ -3344,16 +3356,16 @@ scan_unit_for_symbols (struct comp_unit *unit)
return FALSE;
nested_funcs[nesting_level].func = 0;
/* PR 27484: We must scan the DIEs twice. The first time we look for
function and variable tags and accumulate them into their respective
tables. The second time through we process the attributes of the
functions/variables and augment the table entries. */
while (nesting_level >= 0)
{
unsigned int abbrev_number, bytes_read, i;
struct abbrev_info *abbrev;
struct attribute attr;
struct funcinfo *func;
struct varinfo *var;
bfd_vma low_pc = 0;
bfd_vma high_pc = 0;
bfd_boolean high_pc_relative = FALSE;
bfd_uint64_t current_offset;
/* PR 17512: file: 9f405d9d. */
@ -3365,7 +3377,7 @@ scan_unit_for_symbols (struct comp_unit *unit)
FALSE, info_ptr_end);
info_ptr += bytes_read;
if (! abbrev_number)
if (abbrev_number == 0)
{
nesting_level--;
continue;
@ -3400,6 +3412,7 @@ scan_unit_for_symbols (struct comp_unit *unit)
goto fail;
func->tag = abbrev->tag;
func->prev_func = unit->function_table;
func->unit_offset = current_offset;
unit->function_table = func;
unit->number_of_functions++;
BFD_ASSERT (!unit->cached);
@ -3420,6 +3433,7 @@ scan_unit_for_symbols (struct comp_unit *unit)
|| abbrev->tag == DW_TAG_member)
{
size_t amt = sizeof (struct varinfo);
var = (struct varinfo *) bfd_zalloc (abfd, amt);
if (var == NULL)
goto fail;
@ -3438,6 +3452,89 @@ scan_unit_for_symbols (struct comp_unit *unit)
nested_funcs[nesting_level].func = 0;
}
for (i = 0; i < abbrev->num_attrs; ++i)
{
struct attribute attr;
info_ptr = read_attribute (&attr, &abbrev->attrs[i],
unit, info_ptr, info_ptr_end);
if (info_ptr == NULL)
goto fail;
}
if (abbrev->has_children)
{
nesting_level++;
if (nesting_level >= nested_funcs_size)
{
struct nest_funcinfo *tmp;
nested_funcs_size *= 2;
tmp = (struct nest_funcinfo *)
bfd_realloc (nested_funcs,
nested_funcs_size * sizeof (*nested_funcs));
if (tmp == NULL)
goto fail;
nested_funcs = tmp;
}
nested_funcs[nesting_level].func = 0;
}
}
/* This is the second pass over the abbrevs. */
info_ptr = unit->first_child_die_ptr;
nesting_level = 0;
while (nesting_level >= 0)
{
unsigned int abbrev_number, bytes_read, i;
struct abbrev_info *abbrev;
struct attribute attr;
struct funcinfo *func;
struct varinfo *var;
bfd_vma low_pc = 0;
bfd_vma high_pc = 0;
bfd_boolean high_pc_relative = FALSE;
bfd_uint64_t current_offset;
/* PR 17512: file: 9f405d9d. */
if (info_ptr >= info_ptr_end)
goto fail;
current_offset = info_ptr - unit->info_ptr_unit;
abbrev_number = _bfd_safe_read_leb128 (abfd, info_ptr, &bytes_read,
FALSE, info_ptr_end);
info_ptr += bytes_read;
if (! abbrev_number)
{
nesting_level--;
continue;
}
abbrev = lookup_abbrev (abbrev_number, unit->abbrevs);
/* This should have been handled above. */
BFD_ASSERT (abbrev != NULL);
func = NULL;
var = NULL;
if (abbrev->tag == DW_TAG_subprogram
|| abbrev->tag == DW_TAG_entry_point
|| abbrev->tag == DW_TAG_inlined_subroutine)
{
func = lookup_func_by_offset (current_offset, unit->function_table);
if (func == NULL)
goto fail;
}
else if (abbrev->tag == DW_TAG_variable
|| abbrev->tag == DW_TAG_member)
{
var = lookup_var_by_offset (current_offset, unit->variable_table);
if (var == NULL)
goto fail;
}
for (i = 0; i < abbrev->num_attrs; ++i)
{
info_ptr = read_attribute (&attr, &abbrev->attrs[i],
@ -3532,7 +3629,7 @@ scan_unit_for_symbols (struct comp_unit *unit)
{
_bfd_error_handler (_("DWARF error: could not find "
"variable specification "
"at offset %lx"),
"at offset 0x%lx"),
(unsigned long) attr.u.val);
break;
}
@ -3604,6 +3701,9 @@ scan_unit_for_symbols (struct comp_unit *unit)
}
}
if (abbrev->has_children)
nesting_level++;
if (high_pc_relative)
high_pc += low_pc;
@ -3612,25 +3712,6 @@ scan_unit_for_symbols (struct comp_unit *unit)
if (!arange_add (unit, &func->arange, low_pc, high_pc))
goto fail;
}
if (abbrev->has_children)
{
nesting_level++;
if (nesting_level >= nested_funcs_size)
{
struct nest_funcinfo *tmp;
nested_funcs_size *= 2;
tmp = (struct nest_funcinfo *)
bfd_realloc (nested_funcs,
nested_funcs_size * sizeof (*nested_funcs));
if (tmp == NULL)
goto fail;
nested_funcs = tmp;
}
nested_funcs[nesting_level].func = 0;
}
}
free (nested_funcs);