gdb/dwarf: access m_info_ptr directly instead of passing info_ptr around
The few methods of cutu_reader that read DIEs into memory generally
receive an info_ptr that says where to start reading and return another
one (either by return value or parameter) indicating where the caller
should continue reading.
We can avoid all this passing around by having these methods access
m_info_ptr directly. This allows changing some methods that read DIEs
to return `die_info *`, instead of returning it by parameter, which just
makes the code simpler to read, I think.
The only method that meaningfully reads and writes m_info_ptr (except
the places that initially set it up) is read_full_die_1. It reads and
increments m_info_ptr once to read the abbrev and once again to read
each attribute. Other methods use it for logging.
The methods cutu_reader::read_attribute and
cutu_reader::read_attribute_value do not touch m_info_ptr directly,
because they are used in cooked-indexer.c, which appears to read some
things in a non-linear fashion, unlike cutu_reader's DIE-reading
methods. The cooked indexer calls cutu_reader::info_ptr to get the
m_info_ptr value just after the top-level DIE, and then it does its own
attribute reading after that.
Change-Id: I251f63d13d453a2827b21349760da033171880e2
Approved-By: Tom Tromey <tom@tromey.com>
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 3ff7a82..cfd5efe 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -2769,8 +2769,8 @@ cutu_reader::init_cu_die_reader (dwarf2_cu *cu, dwarf2_section_info *section,
attribute of the referencing CU. At most one of STUB_COMP_UNIT_DIE and
STUB_COMP_DIR may be non-NULL.
- *RESULT_READER,*RESULT_INFO_PTR,*RESULT_TOP_LEVEL_DIE
- are filled in with the info of the DIE from the DWO file.
+ *RESULT_READER and *RESULT_TOP_LEVEL_DIE are filled in with the info of the
+ DIE from the DWO file.
*RESULT_DWO_ABBREV_TABLE will be filled in with the abbrev table allocated
from the dwo. Since *RESULT_READER references this abbrev table, it must be
@@ -2782,7 +2782,6 @@ int
cutu_reader::read_cutu_die_from_dwo (dwarf2_cu *cu, dwo_unit *dwo_unit,
die_info *stub_comp_unit_die,
const char *stub_comp_dir,
- const gdb_byte **result_info_ptr,
die_info **result_top_level_die,
abbrev_table_up *result_dwo_abbrev_table)
{
@@ -2790,7 +2789,6 @@ cutu_reader::read_cutu_die_from_dwo (dwarf2_cu *cu, dwo_unit *dwo_unit,
dwarf2_per_cu *per_cu = cu->per_cu;
struct objfile *objfile = per_objfile->objfile;
bfd *abfd;
- const gdb_byte *begin_info_ptr, *info_ptr;
struct dwarf2_section_info *dwo_abbrev_section;
/* At most one of these may be provided. */
@@ -2857,17 +2855,17 @@ cutu_reader::read_cutu_die_from_dwo (dwarf2_cu *cu, dwo_unit *dwo_unit,
dwarf2_section_info *section = dwo_unit->section;
section->read (objfile);
abfd = section->get_bfd_owner ();
- begin_info_ptr = info_ptr = (section->buffer
- + to_underlying (dwo_unit->sect_off));
+ m_info_ptr = section->buffer + to_underlying (dwo_unit->sect_off);
+ const gdb_byte *begin_info_ptr = m_info_ptr;
dwo_abbrev_section = &dwo_unit->dwo_file->sections.abbrev;
if (per_cu->is_debug_types)
{
signatured_type *sig_type = (struct signatured_type *) per_cu;
- info_ptr = read_and_check_comp_unit_head (per_objfile, &cu->header,
- section, dwo_abbrev_section,
- info_ptr, rcuh_kind::TYPE);
+ m_info_ptr = read_and_check_comp_unit_head (per_objfile, &cu->header,
+ section, dwo_abbrev_section,
+ m_info_ptr, rcuh_kind::TYPE);
/* This is not an assert because it can be caused by bad debug info. */
if (sig_type->signature != cu->header.signature)
{
@@ -2892,9 +2890,10 @@ cutu_reader::read_cutu_die_from_dwo (dwarf2_cu *cu, dwo_unit *dwo_unit,
}
else
{
- info_ptr = read_and_check_comp_unit_head (per_objfile, &cu->header,
- section, dwo_abbrev_section,
- info_ptr, rcuh_kind::COMPILE);
+ m_info_ptr
+ = read_and_check_comp_unit_head (per_objfile, &cu->header, section,
+ dwo_abbrev_section, m_info_ptr,
+ rcuh_kind::COMPILE);
gdb_assert (dwo_unit->sect_off == cu->header.sect_off);
/* For DWOs coming from DWP files, we don't know the CU length
until now. */
@@ -2911,16 +2910,15 @@ cutu_reader::read_cutu_die_from_dwo (dwarf2_cu *cu, dwo_unit *dwo_unit,
has the benefit of simplifying the rest of the code - all the
work to maintain the illusion of a single
DW_TAG_{compile,type}_unit DIE is done here. */
- info_ptr = this->read_toplevel_die (result_top_level_die, info_ptr,
- gdb::make_array_view (attributes,
- next_attr_idx));
+ *result_top_level_die
+ = this->read_toplevel_die (gdb::make_array_view (attributes,
+ next_attr_idx));
/* Skip dummy compilation units. */
- if (info_ptr >= begin_info_ptr + dwo_unit->length
- || peek_abbrev_code (abfd, info_ptr) == 0)
+ if (m_info_ptr >= begin_info_ptr + dwo_unit->length
+ || peek_abbrev_code (abfd, m_info_ptr) == 0)
return 0;
- *result_info_ptr = info_ptr;
return 1;
}
@@ -3024,8 +3022,7 @@ cutu_reader::init_tu_and_read_dwo_dies (dwarf2_per_cu *this_cu,
if (read_cutu_die_from_dwo (cu, sig_type->dwo_unit,
NULL /* stub_comp_unit_die */,
sig_type->dwo_unit->dwo_file->comp_dir,
- &m_info_ptr, &m_top_level_die,
- &m_dwo_abbrev_table)
+ &m_top_level_die, &m_dwo_abbrev_table)
== 0)
{
/* Dummy die. */
@@ -3189,7 +3186,7 @@ cutu_reader::cutu_reader (dwarf2_per_cu *this_cu,
/* Read the top level CU/TU die. */
this->init_cu_die_reader (cu, section, NULL, abbrev_table);
- m_info_ptr = this->read_toplevel_die (&m_top_level_die, m_info_ptr);
+ m_top_level_die = this->read_toplevel_die ();
if (skip_partial && m_top_level_die->tag == DW_TAG_partial_unit)
m_dummy_p = true;
@@ -3222,8 +3219,7 @@ cutu_reader::cutu_reader (dwarf2_per_cu *this_cu,
if (dwo_unit != NULL)
{
if (read_cutu_die_from_dwo (cu, dwo_unit, m_top_level_die,
- nullptr, &m_info_ptr,
- &dwo_comp_unit_die,
+ nullptr, &dwo_comp_unit_die,
&m_dwo_abbrev_table)
== 0)
{
@@ -3290,7 +3286,6 @@ cutu_reader::cutu_reader (dwarf2_per_cu *this_cu,
struct objfile *objfile = per_objfile->objfile;
struct dwarf2_section_info *section = this_cu->section;
bfd *abfd = section->get_bfd_owner ();
- const gdb_byte *begin_info_ptr, *info_ptr;
gdb_assert (parent_cu != nullptr);
gdb_assert (dwo_file != nullptr);
@@ -3309,12 +3304,14 @@ cutu_reader::cutu_reader (dwarf2_per_cu *this_cu,
m_new_cu = std::make_unique<dwarf2_cu> (this_cu, per_objfile);
- begin_info_ptr = info_ptr = section->buffer + to_underlying (this_cu->sect_off);
- info_ptr = read_and_check_comp_unit_head (per_objfile, &m_new_cu->header,
- section, abbrev_section, info_ptr,
- (this_cu->is_debug_types
- ? rcuh_kind::TYPE
- : rcuh_kind::COMPILE));
+ m_info_ptr = section->buffer + to_underlying (this_cu->sect_off);
+ const gdb_byte *begin_info_ptr = m_info_ptr;
+ m_info_ptr
+ = read_and_check_comp_unit_head (per_objfile, &m_new_cu->header, section,
+ abbrev_section, m_info_ptr,
+ (this_cu->is_debug_types
+ ? rcuh_kind::TYPE
+ : rcuh_kind::COMPILE));
m_new_cu->str_offsets_base = parent_cu->str_offsets_base;
m_new_cu->addr_base = parent_cu->addr_base;
@@ -3322,8 +3319,8 @@ cutu_reader::cutu_reader (dwarf2_per_cu *this_cu,
this_cu->set_length (m_new_cu->header.get_length_with_initial ());
/* Skip dummy compilation units. */
- if (info_ptr >= begin_info_ptr + this_cu->length ()
- || peek_abbrev_code (abfd, info_ptr) == 0)
+ if (m_info_ptr >= begin_info_ptr + this_cu->length ()
+ || peek_abbrev_code (abfd, m_info_ptr) == 0)
m_dummy_p = true;
else
{
@@ -3334,7 +3331,7 @@ cutu_reader::cutu_reader (dwarf2_per_cu *this_cu,
this->init_cu_die_reader (m_new_cu.get (), section, dwo_file,
m_abbrev_table_holder.get ());
- info_ptr = this->read_toplevel_die (&m_top_level_die, info_ptr);
+ m_top_level_die = this->read_toplevel_die ();
}
prepare_one_comp_unit (m_new_cu.get (), pretend_language);
@@ -4404,15 +4401,14 @@ load_full_comp_unit (dwarf2_per_cu *this_cu,
return;
struct dwarf2_cu *cu = reader.cu ();
- const gdb_byte *info_ptr = reader.info_ptr ();
gdb_assert (cu->die_hash.empty ());
cu->die_hash.reserve (cu->header.get_length_without_initial () / 12);
if (reader.top_level_die ()->has_children)
reader.top_level_die ()->child
- = reader.read_die_and_siblings (reader.info_ptr (), &info_ptr,
- reader.top_level_die ());
+ = reader.read_die_and_siblings (reader.top_level_die ());
+
cu->dies = reader.top_level_die ();
/* comp_unit_die is not stored in die_hash, no need. */
@@ -14531,37 +14527,26 @@ read_unspecified_type (struct die_info *die, struct dwarf2_cu *cu)
/* Read a single die and all its descendents. Set the die's sibling
field to NULL; set other fields in the die correctly, and set all
- of the descendents' fields correctly. Set *NEW_INFO_PTR to the
- location of the info_ptr after reading all of those dies. PARENT
- is the parent of the die in question. */
+ of the descendents' fields correctly. PARENT is the parent of the
+ die in question. */
die_info *
-cutu_reader::read_die_and_children (const gdb_byte *info_ptr,
- const gdb_byte **new_info_ptr,
- die_info *parent)
+cutu_reader::read_die_and_children (die_info *parent)
{
- struct die_info *die;
-
+ die_info *die = this->read_full_die_1 (0, true);
- const gdb_byte *cur_ptr = this->read_full_die_1 (&die, info_ptr, 0, true);
- if (die == NULL)
- {
- *new_info_ptr = cur_ptr;
- return NULL;
- }
+ if (die == nullptr)
+ return nullptr;
bool inserted = m_cu->die_hash.emplace (die).second;
gdb_assert (inserted);
if (die->has_children)
- die->child = this->read_die_and_siblings_1 (cur_ptr, new_info_ptr, die);
+ die->child = this->read_die_and_siblings_1 (die);
else
- {
- die->child = NULL;
- *new_info_ptr = cur_ptr;
- }
+ die->child = nullptr;
- die->sibling = NULL;
+ die->sibling = nullptr;
die->parent = parent;
return die;
}
@@ -14571,27 +14556,19 @@ cutu_reader::read_die_and_children (const gdb_byte *info_ptr,
in read_die_and_children. */
die_info *
-cutu_reader::read_die_and_siblings_1 (const gdb_byte *info_ptr,
- const gdb_byte **new_info_ptr,
- die_info *parent)
+cutu_reader::read_die_and_siblings_1 (die_info *parent)
{
- struct die_info *first_die, *last_sibling;
- const gdb_byte *cur_ptr;
+ die_info *first_die = nullptr;
+ die_info *last_sibling = nullptr;
- cur_ptr = info_ptr;
- first_die = last_sibling = NULL;
-
- while (1)
+ while (true)
{
- die_info *die = this->read_die_and_children (cur_ptr, &cur_ptr, parent);
+ die_info *die = this->read_die_and_children (parent);
- if (die == NULL)
- {
- *new_info_ptr = cur_ptr;
- return first_die;
- }
+ if (die == nullptr)
+ return first_die;
- if (!first_die)
+ if (first_die == nullptr)
first_die = die;
else
last_sibling->sibling = die;
@@ -14606,18 +14583,16 @@ cutu_reader::read_die_and_siblings_1 (const gdb_byte *info_ptr,
This the main entry point for reading a DIE and all its children. */
die_info *
-cutu_reader::read_die_and_siblings (const gdb_byte *info_ptr,
- const gdb_byte **new_info_ptr,
- die_info *parent)
+cutu_reader::read_die_and_siblings (die_info *parent)
{
- struct die_info *die = read_die_and_siblings_1 (info_ptr,
- new_info_ptr, parent);
+ const gdb_byte *begin_info_ptr = m_info_ptr;
+ struct die_info *die = this->read_die_and_siblings_1 (parent);
if (dwarf_die_debug)
{
- gdb_printf (gdb_stdlog, "Read die from %s@0x%x of %s:\n",
+ gdb_printf (gdb_stdlog, "Read die from %s@0x%tx of %s:\n",
m_die_section->get_name (),
- (unsigned) (info_ptr - m_die_section->buffer),
+ begin_info_ptr - m_die_section->buffer,
bfd_get_filename (m_abfd));
die->dump (dwarf_die_debug);
}
@@ -14627,27 +14602,26 @@ cutu_reader::read_die_and_siblings (const gdb_byte *info_ptr,
/* Read a die and all its attributes, leave space for NUM_EXTRA_ATTRS
attributes.
+
The caller is responsible for filling in the extra attributes
- and updating (*DIEP)->num_attrs.
- Set DIEP to point to a newly allocated die with its information,
- except for its child, sibling, and parent fields. */
+ and updating die_info::num_attrs.
-const gdb_byte *
-cutu_reader::read_full_die_1 (die_info **diep, const gdb_byte *info_ptr,
- int num_extra_attrs, bool allow_reprocess)
+ Return a newly allocated die with its information, except for its
+ child, sibling, and parent fields. */
+
+die_info *
+cutu_reader::read_full_die_1 (int num_extra_attrs, bool allow_reprocess)
{
- unsigned int abbrev_number, bytes_read, i;
+ unsigned int bytes_read, i;
const struct abbrev_info *abbrev;
- struct die_info *die;
- sect_offset sect_off = (sect_offset) (info_ptr - m_buffer);
- abbrev_number = read_unsigned_leb128 (m_abfd, info_ptr, &bytes_read);
- info_ptr += bytes_read;
- if (!abbrev_number)
- {
- *diep = NULL;
- return info_ptr;
- }
+ sect_offset sect_off = static_cast<sect_offset> (m_info_ptr - m_buffer);
+ unsigned int abbrev_number
+ = read_unsigned_leb128 (m_abfd, m_info_ptr, &bytes_read);
+ m_info_ptr += bytes_read;
+
+ if (abbrev_number == 0)
+ return nullptr;
abbrev = m_abbrev_table->lookup_abbrev (abbrev_number);
if (!abbrev)
@@ -14655,8 +14629,8 @@ cutu_reader::read_full_die_1 (die_info **diep, const gdb_byte *info_ptr,
"could not find abbrev number %d [in module %s]"),
abbrev_number, bfd_get_filename (m_abfd));
- die = die_info::allocate (&m_cu->comp_unit_obstack,
- abbrev->num_attrs + num_extra_attrs);
+ die_info *die = die_info::allocate (&m_cu->comp_unit_obstack,
+ abbrev->num_attrs + num_extra_attrs);
die->sect_off = sect_off;
die->tag = abbrev->tag;
die->abbrev = abbrev_number;
@@ -14668,63 +14642,62 @@ cutu_reader::read_full_die_1 (die_info **diep, const gdb_byte *info_ptr,
die->num_attrs = abbrev->num_attrs;
for (i = 0; i < abbrev->num_attrs; ++i)
- info_ptr = this->read_attribute (&die->attrs[i], &abbrev->attrs[i],
- info_ptr, allow_reprocess);
+ m_info_ptr = this->read_attribute (&die->attrs[i], &abbrev->attrs[i],
+ m_info_ptr, allow_reprocess);
- *diep = die;
- return info_ptr;
+ return die;
}
/* Read a die and all its attributes.
- Set DIEP to point to a newly allocated die with its information,
- except for its child, sibling, and parent fields. */
-const gdb_byte *
-cutu_reader::read_toplevel_die (die_info **diep, const gdb_byte *info_ptr,
- gdb::array_view<attribute *> extra_attrs)
+ Return a newly allocated die with its information, except for its
+ child, sibling, and parent fields. */
+
+die_info *
+cutu_reader::read_toplevel_die (gdb::array_view<attribute *> extra_attrs)
{
- const gdb_byte *result
- = this->read_full_die_1 (diep, info_ptr, extra_attrs.size (), false);
+ const gdb_byte *begin_info_ptr = m_info_ptr;
+ die_info *die = this->read_full_die_1 (extra_attrs.size (), false);
/* Copy in the extra attributes, if any. */
- attribute *next = &(*diep)->attrs[(*diep)->num_attrs];
+ attribute *next = &die->attrs[die->num_attrs];
for (attribute *extra : extra_attrs)
*next++ = *extra;
- struct attribute *attr = (*diep)->attr (DW_AT_str_offsets_base);
+ struct attribute *attr = die->attr (DW_AT_str_offsets_base);
if (attr != nullptr && attr->form_is_unsigned ())
m_cu->str_offsets_base = attr->as_unsigned ();
- attr = (*diep)->attr (DW_AT_loclists_base);
+ attr = die->attr (DW_AT_loclists_base);
if (attr != nullptr)
m_cu->loclist_base = attr->as_unsigned ();
- auto maybe_addr_base = (*diep)->addr_base ();
+ auto maybe_addr_base = die->addr_base ();
if (maybe_addr_base.has_value ())
m_cu->addr_base = *maybe_addr_base;
- attr = (*diep)->attr (DW_AT_rnglists_base);
+ attr = die->attr (DW_AT_rnglists_base);
if (attr != nullptr)
m_cu->rnglists_base = attr->as_unsigned ();
- for (int i = 0; i < (*diep)->num_attrs; ++i)
+ for (int i = 0; i < die->num_attrs; ++i)
{
- if ((*diep)->attrs[i].form_requires_reprocessing ())
- this->read_attribute_reprocess (&(*diep)->attrs[i], (*diep)->tag);
+ if (die->attrs[i].form_requires_reprocessing ())
+ this->read_attribute_reprocess (&die->attrs[i], die->tag);
}
- (*diep)->num_attrs += extra_attrs.size ();
+ die->num_attrs += extra_attrs.size ();
if (dwarf_die_debug)
{
- gdb_printf (gdb_stdlog, "Read die from %s@0x%x of %s:\n",
+ gdb_printf (gdb_stdlog, "Read die from %s@0x%tx of %s:\n",
m_die_section->get_name (),
- (unsigned) (info_ptr - m_die_section->buffer),
+ (begin_info_ptr - m_die_section->buffer),
bfd_get_filename (m_abfd));
- (*diep)->dump (dwarf_die_debug);
+ die->dump (dwarf_die_debug);
}
- return result;
+ return die;
}
struct compunit_symtab *
@@ -19137,15 +19110,14 @@ read_signatured_type (signatured_type *sig_type,
if (!reader.is_dummy ())
{
struct dwarf2_cu *cu = reader.cu ();
- const gdb_byte *info_ptr = reader.info_ptr ();
gdb_assert (cu->die_hash.empty ());
cu->die_hash.reserve (cu->header.get_length_without_initial () / 12);
if (reader.top_level_die ()->has_children)
reader.top_level_die ()->child
- = reader.read_die_and_siblings (info_ptr, &info_ptr,
- reader.top_level_die ());
+ = reader.read_die_and_siblings (reader.top_level_die ());
+
cu->dies = reader.top_level_die ();
/* comp_unit_die is not stored in die_hash, no need. */
diff --git a/gdb/dwarf2/read.h b/gdb/dwarf2/read.h
index a8d7428..3f99b39 100644
--- a/gdb/dwarf2/read.h
+++ b/gdb/dwarf2/read.h
@@ -952,9 +952,7 @@ class cutu_reader
return std::move (m_abbrev_table_holder);
}
- die_info *read_die_and_siblings (const gdb_byte *info_ptr,
- const gdb_byte **new_info_ptr,
- die_info *parent);
+ die_info *read_die_and_siblings (die_info *parent);
const gdb_byte *read_attribute (attribute *attr, const attr_abbrev *abbrev,
const gdb_byte *info_ptr,
@@ -987,26 +985,21 @@ class cutu_reader
int read_cutu_die_from_dwo (dwarf2_cu *cu, dwo_unit *dwo_unit,
die_info *stub_comp_unit_die,
const char *stub_comp_dir,
- const gdb_byte **result_info_ptr,
die_info **result_comp_unit_die,
abbrev_table_up *result_dwo_abbrev_table);
void prepare_one_comp_unit (struct dwarf2_cu *cu,
enum language pretend_language);
- const gdb_byte *read_toplevel_die (die_info **diep, const gdb_byte *info_ptr,
- gdb::array_view<attribute *> extra_attrs
- = {});
+ /* Helpers to build the in-memory DIE tree. */
- die_info *read_die_and_siblings_1 (const gdb_byte *, const gdb_byte **,
- die_info *);
+ die_info *read_toplevel_die (gdb::array_view<attribute *> extra_attrs = {});
- die_info *read_die_and_children (const gdb_byte *info_ptr,
- const gdb_byte **new_info_ptr,
- die_info *parent);
+ die_info *read_die_and_siblings_1 (die_info *parent);
- const gdb_byte *read_full_die_1 (die_info **diep, const gdb_byte *info_ptr,
- int num_extra_attrs, bool allow_reprocess);
+ die_info *read_die_and_children (die_info *parent);
+
+ die_info *read_full_die_1 (int num_extra_attrs, bool allow_reprocess);
const gdb_byte *read_attribute_value (attribute *attr, unsigned form,
LONGEST implicit_const,
