dwarf2out.c (struct external_ref, [...]): New.

* dwarf2out.c (struct external_ref, build_local_stub): New.
	(hash_external_ref, external_ref_eq, lookup_external_ref): New.
	(optimize_external_refs, optimize_external_refs_1): New.
	(change_AT_die_ref): New.
	(clone_as_declaration): Add DW_AT_signature when cloning a declaration.
	(build_abbrev_table): Take the external refs hashtable.
	(output_comp_unit): Get it from optimize_external_refs and pass it in.

From-SVN: r187116
This commit is contained in:
Jason Merrill 2012-05-03 15:55:16 -04:00 committed by Jason Merrill
parent f95f017c42
commit 05688bf703
4 changed files with 210 additions and 11 deletions

View File

@ -1,3 +1,13 @@
2012-05-02 Jason Merrill <jason@redhat.com>
* dwarf2out.c (struct external_ref, build_local_stub): New.
(hash_external_ref, external_ref_eq, lookup_external_ref): New.
(optimize_external_refs, optimize_external_refs_1): New.
(change_AT_die_ref): New.
(clone_as_declaration): Add DW_AT_signature when cloning a declaration.
(build_abbrev_table): Take the external refs hashtable.
(output_comp_unit): Get it from optimize_external_refs and pass it in.
2012-05-03 Jan Hubicka <jh@suse.cz>
PR middle-end/53093

View File

@ -2986,7 +2986,7 @@ static void htab_cu_del (void *);
static int check_duplicate_cu (dw_die_ref, htab_t, unsigned *);
static void record_comdat_symbol_number (dw_die_ref, htab_t, unsigned);
static void add_sibling_attributes (dw_die_ref);
static void build_abbrev_table (dw_die_ref);
static void build_abbrev_table (dw_die_ref, htab_t);
static void output_location_lists (dw_die_ref);
static int constant_size (unsigned HOST_WIDE_INT);
static unsigned long size_of_die (dw_die_ref);
@ -3718,6 +3718,16 @@ add_AT_die_ref (dw_die_ref die, enum dwarf_attribute attr_kind, dw_die_ref targ_
add_dwarf_attr (die, &attr);
}
/* Change DIE reference REF to point to NEW_DIE instead. */
static inline void
change_AT_die_ref (dw_attr_ref ref, dw_die_ref new_die)
{
gcc_assert (ref->dw_attr_val.val_class == dw_val_class_die_ref);
ref->dw_attr_val.v.val_die_ref.die = new_die;
ref->dw_attr_val.v.val_die_ref.external = 0;
}
/* Add an AT_specification attribute to a DIE, and also make the back
pointer from the specification to the definition. */
@ -6277,7 +6287,12 @@ clone_as_declaration (dw_die_ref die)
/* If the DIE is a specification, just clone its declaration DIE. */
decl = get_AT_ref (die, DW_AT_specification);
if (decl != NULL)
return clone_die (decl);
{
clone = clone_die (decl);
if (die->comdat_type_p)
add_AT_die_ref (clone, DW_AT_signature, die);
return clone;
}
clone = ggc_alloc_cleared_die_node ();
clone->die_tag = die->die_tag;
@ -6816,13 +6831,159 @@ output_location_lists (dw_die_ref die)
FOR_EACH_CHILD (die, c, output_location_lists (c));
}
/* We want to limit the number of external references, because they are
larger than local references: a relocation takes multiple words, and
even a sig8 reference is always eight bytes, whereas a local reference
can be as small as one byte (though DW_FORM_ref is usually 4 in GCC).
So if we encounter multiple external references to the same type DIE, we
make a local typedef stub for it and redirect all references there.
This is the element of the hash table for keeping track of these
references. */
struct external_ref
{
dw_die_ref type;
dw_die_ref stub;
unsigned n_refs;
};
/* Hash an external_ref. */
static hashval_t
hash_external_ref (const void *p)
{
const struct external_ref *r = (const struct external_ref *)p;
return htab_hash_pointer (r->type);
}
/* Compare external_refs. */
static int
external_ref_eq (const void *p1, const void *p2)
{
const struct external_ref *r1 = (const struct external_ref *)p1;
const struct external_ref *r2 = (const struct external_ref *)p2;
return r1->type == r2->type;
}
/* Return a pointer to the external_ref for references to DIE. */
static struct external_ref *
lookup_external_ref (htab_t map, dw_die_ref die)
{
struct external_ref ref, *ref_p;
void ** slot;
ref.type = die;
slot = htab_find_slot (map, &ref, INSERT);
if (*slot != HTAB_EMPTY_ENTRY)
return (struct external_ref *) *slot;
ref_p = XCNEW (struct external_ref);
ref_p->type = die;
*slot = ref_p;
return ref_p;
}
/* Subroutine of optimize_external_refs, below.
If we see a type skeleton, record it as our stub. If we see external
references, remember how many we've seen. */
static void
optimize_external_refs_1 (dw_die_ref die, htab_t map)
{
dw_die_ref c;
dw_attr_ref a;
unsigned ix;
struct external_ref *ref_p;
if (is_type_die (die)
&& (c = get_AT_ref (die, DW_AT_signature)))
{
/* This is a local skeleton; use it for local references. */
ref_p = lookup_external_ref (map, c);
ref_p->stub = die;
}
/* Scan the DIE references, and remember any that refer to DIEs from
other CUs (i.e. those which are not marked). */
FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
if (AT_class (a) == dw_val_class_die_ref
&& (c = AT_ref (a))->die_mark == 0
&& is_type_die (c))
{
ref_p = lookup_external_ref (map, c);
ref_p->n_refs++;
}
FOR_EACH_CHILD (die, c, optimize_external_refs_1 (c, map));
}
/* htab_traverse callback function for optimize_external_refs, below. SLOT
points to an external_ref, DATA is the CU we're processing. If we don't
already have a local stub, and we have multiple refs, build a stub. */
static int
build_local_stub (void **slot, void *data)
{
struct external_ref *ref_p = (struct external_ref *)*slot;
dw_die_ref cu = (dw_die_ref) data;
dw_die_ref type = ref_p->type;
dw_die_ref stub = NULL;
if (ref_p->stub == NULL && ref_p->n_refs > 1)
{
if (!dwarf_strict)
{
/* If we aren't being strict, use a typedef with no name
to just forward to the real type. In strict DWARF, a
typedef must have a name. */
stub = new_die (DW_TAG_typedef, cu, NULL_TREE);
add_AT_die_ref (stub, DW_AT_type, type);
}
else if (type->comdat_type_p)
{
/* If we refer to this type via sig8, we can use a simple
declaration; this is larger than the typedef, but strictly
correct. */
stub = new_die (type->die_tag, cu, NULL_TREE);
add_AT_string (stub, DW_AT_name, get_AT_string (type, DW_AT_name));
add_AT_flag (stub, DW_AT_declaration, 1);
add_AT_die_ref (stub, DW_AT_signature, type);
}
if (stub)
{
stub->die_mark++;
ref_p->stub = stub;
}
}
return 1;
}
/* DIE is a unit; look through all the DIE references to see if there are
any external references to types, and if so, create local stubs for
them which will be applied in build_abbrev_table. This is useful because
references to local DIEs are smaller. */
static htab_t
optimize_external_refs (dw_die_ref die)
{
htab_t map = htab_create (10, hash_external_ref, external_ref_eq, free);
optimize_external_refs_1 (die, map);
htab_traverse (map, build_local_stub, die);
return map;
}
/* The format of each DIE (and its attribute value pairs) is encoded in an
abbreviation table. This routine builds the abbreviation table and assigns
a unique abbreviation id for each abbreviation entry. The children of each
die are visited recursively. */
static void
build_abbrev_table (dw_die_ref die)
build_abbrev_table (dw_die_ref die, htab_t extern_map)
{
unsigned long abbrev_id;
unsigned int n_alloc;
@ -6830,14 +6991,22 @@ build_abbrev_table (dw_die_ref die)
dw_attr_ref a;
unsigned ix;
/* Scan the DIE references, and mark as external any that refer to
DIEs from other CUs (i.e. those which are not marked). */
/* Scan the DIE references, and replace any that refer to
DIEs from other CUs (i.e. those which are not marked) with
the local stubs we built in optimize_external_refs. */
FOR_EACH_VEC_ELT (dw_attr_node, die->die_attr, ix, a)
if (AT_class (a) == dw_val_class_die_ref
&& AT_ref (a)->die_mark == 0)
&& (c = AT_ref (a))->die_mark == 0)
{
struct external_ref *ref_p;
gcc_assert (AT_ref (a)->comdat_type_p || AT_ref (a)->die_id.die_symbol);
set_AT_ref_external (a, 1);
ref_p = lookup_external_ref (extern_map, c);
if (ref_p->stub && ref_p->stub != die)
change_AT_die_ref (a, ref_p->stub);
else
/* We aren't changing this reference, so mark it external. */
set_AT_ref_external (a, 1);
}
for (abbrev_id = 1; abbrev_id < abbrev_die_table_in_use; ++abbrev_id)
@ -6888,7 +7057,7 @@ build_abbrev_table (dw_die_ref die)
}
die->die_abbrev = abbrev_id;
FOR_EACH_CHILD (die, c, build_abbrev_table (c));
FOR_EACH_CHILD (die, c, build_abbrev_table (c, extern_map));
}
/* Return the power-of-two number of bytes necessary to represent VALUE. */
@ -7811,6 +7980,7 @@ output_comp_unit (dw_die_ref die, int output_if_empty)
{
const char *secname, *oldsym;
char *tmp;
htab_t extern_map;
/* Unless we are outputting main CU, we may throw away empty ones. */
if (!output_if_empty && die->die_child == NULL)
@ -7823,7 +7993,11 @@ output_comp_unit (dw_die_ref die, int output_if_empty)
this CU so we know which get local refs. */
mark_dies (die);
build_abbrev_table (die);
extern_map = optimize_external_refs (die);
build_abbrev_table (die, extern_map);
htab_delete (extern_map);
/* Initialize the beginning DIE offset - and calculate sizes/offsets. */
next_die_offset = DWARF_COMPILE_UNIT_HEADER_SIZE;
@ -7870,11 +8044,16 @@ output_comdat_type_unit (comdat_type_node *node)
#if defined (OBJECT_FORMAT_ELF)
tree comdat_key;
#endif
htab_t extern_map;
/* First mark all the DIEs in this CU so we know which get local refs. */
mark_dies (node->root_die);
build_abbrev_table (node->root_die);
extern_map = optimize_external_refs (node->root_die);
build_abbrev_table (node->root_die, extern_map);
htab_delete (extern_map);
/* Initialize the beginning DIE offset - and calculate sizes/offsets. */
next_die_offset = DWARF_COMDAT_TYPE_UNIT_HEADER_SIZE;

View File

@ -1,5 +1,7 @@
2012-05-03 Jason Merrill <jason@redhat.com>
* g++.dg/debug/dwarf2/nested-3.C: Adjust pattern.
* gcc.dg/debug/dwarf2/dups-types.c: New.
* gcc.dg/debug/dwarf2/dups-types.h: New.

View File

@ -37,6 +37,14 @@ main ()
// .uleb128 0x9 # (DIE (0x34) DW_TAG_class_type)
// .long .LASF0 # DW_AT_name: "Executor"
// # DW_AT_declaration
// .byte 0xa0 # DW_AT_signature
// .byte 0xfe
// .byte 0xe6
// .byte 0x7b
// .byte 0x66
// .byte 0xe9
// .byte 0x38
// .byte 0xf0
// .uleb128 0x5 # (DIE (0x39) DW_TAG_subprogram)
// # DW_AT_external
// .long .LASF1 # DW_AT_name: "CurrentExecutor"
@ -51,4 +59,4 @@ main ()
//
// Hence the scary regexp:
//
// { dg-final { scan-assembler "\[^\n\r\]*\\(DIE \\(0x(\[0-9a-f\]+)\\) DW_TAG_namespace\\)\[\n\r\]+\[^\n\r\]*\"thread\[\^\n\r]+\[\n\r\]+(\[^\n\r\]*\[\n\r\]+)+\[^\n\r\]*\\(DIE \\(0x(\[0-9a-f\]+)\\) DW_TAG_class_type\\)(\[\n\r\]+\[^\n\r\]*)+\"Executor\[^\n\r\]+\[\n\r\]+\[^\n\r\]*DW_AT_declaration\[\n\r\]+\[^\n\r\]*\\(DIE\[^\n\r\]*DW_TAG_subprogram\\)\[\n\r\]+(\[^\n\r\]*\[\n\r\]+)+\[^\n\r\]*\"CurrentExecutor\[^\n\r\]+\[\n\r\]+(\[^\n\r\]*\[\n\r\]+)+(\[^\n\r\]*\[\n\r\]+)+\[^\n\r\]*end of children of DIE 0x\\3\[\n\r]+\[^\n\r\]*end of children of DIE 0x\\1\[\n\r]+" } }
// { dg-final { scan-assembler "\[^\n\r\]*\\(DIE \\(0x(\[0-9a-f\]+)\\) DW_TAG_namespace\\)\[\n\r\]+\[^\n\r\]*\"thread\[\^\n\r]+\[\n\r\]+(\[^\n\r\]*\[\n\r\]+)+\[^\n\r\]*\\(DIE \\(0x(\[0-9a-f\]+)\\) DW_TAG_class_type\\)(\[\n\r\]+\[^\n\r\]*)+\"Executor\[^\n\r\]+\[\n\r\]+\[^\n\r\]*DW_AT_declaration\[\n\r\]+\[^\n\r\]*DW_AT_signature\[^#\]*# \\(DIE\[^\n\r\]*DW_TAG_subprogram\\)\[\n\r\]+(\[^\n\r\]*\[\n\r\]+)+\[^\n\r\]*\"CurrentExecutor\[^\n\r\]+\[\n\r\]+(\[^\n\r\]*\[\n\r\]+)+(\[^\n\r\]*\[\n\r\]+)+\[^\n\r\]*end of children of DIE 0x\\3\[\n\r]+\[^\n\r\]*end of children of DIE 0x\\1\[\n\r]+" } }