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Bug 19355 - Libabigail slow on r300_dri.so

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Profiling abidw --abidiff r300_dri.so, with a r30_dri.so that was run
through dwz shows that a great deal of the time is spent in trying to
get the logical parent of a DIE which has been imported.

To do that, we need to walk the translation unit DIEs again to know
where the DIE we are looking at has been imported.  And doing that
walking again and again, following the accessors of the DIE data
structure from elfutils takes time.

This patch reduces that time by constructing a "trace" of where units
have been imported.  So that looking for the logical parent of a given
DIE doesn't involve walking the DIE tree itself, but rather, walking
the trace, which is a vector.  This proves to be much faster.

In practice, the overall time spent is now less than 12 minutes.  It
was more than 50 minutes before.

	* src/abg-dwarf-reader.cc (struct imported_unit_point): Define new
	type.
	(operator<(const imported_unit_point&, const
	imported_unit_point&)): Define less-than operator for new
	imported_unit_point& type.
	(imported_unit_points_type, tu_die_imported_unit_points_map_type):
	New typedefs.
	(find_lower_bound_in_imported_unit_points): Define new static function.
	(read_context::tu_die_imported_unit_points_map_): New data member.
	(read_context::tu_die_imported_unit_points_map): New getter.
	(die_die_attribute): Define new overload.
	(build_die_parent_relations_under): Take imported_unit_points_type
	output parameter and populate it along the way. Remove the
	overload that takes a read_context as a parameter.
	(build_primary_die_parent_relations_under)
	(build_alternate_die_parent_relations_under): Remove.
	(build_die_parent_maps): Pass an instance of
	imported_unit_points_type to build_die_parent_relations_under.
	(find_import_unit_point_between_dies): Rename one overload of
	find_last_import_unit_point_before_die into this.  Adjust to make
	it find the import point between two offsets.
	(find_import_unit_point_before_die): Rename the other overload of
	find_last_import_unit_point_before_die into this. Adjust to use
	find_import_unit_point_between_dies.
	(get_parent_die): Adjust to use find_import_unit_point_before_die.

Signed-off-by: Dodji Seketeli <dodji@redhat.com>
This commit is contained in:
Dodji Seketeli 2016-01-04 17:47:19 +01:00
parent 658430b921
commit 5a8c000a87
1 changed files with 307 additions and 146 deletions
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423
src/abg-dwarf-reader.cc
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@ -121,6 +121,88 @@ typedef unordered_map<Dwarf_Off, Dwarf_Off> offset_offset_map;
/// value is a vector of smart pointer to a class.
typedef unordered_map<string, classes_type> string_classes_map;
/// The abstraction of the place where a partial unit has been
/// imported. This is what the DW_TAG_imported_unit DIE expresses.
///
/// This type thus contains:
/// - the offset to which the partial unit is imported
/// - the offset of the imported partial unit.
/// - the offset of the imported partial unit.
struct imported_unit_point
{
Dwarf_Off offset_of_import;
Dwarf_Off imported_unit_die_off;
Dwarf_Off imported_unit_cu_off;
Dwarf_Off imported_unit_child_off;
/// Default constructor for @ref the type imported_unit_point.
imported_unit_point ()
: offset_of_import(),
imported_unit_die_off(),
imported_unit_cu_off(),
imported_unit_child_off()
{}
/// Constructor of @ref the type imported_unit_point.
///
/// @param import_off the offset of the point at which the unit has
/// been imported.
imported_unit_point (Dwarf_Off import_off)
: offset_of_import(import_off),
imported_unit_die_off(),
imported_unit_cu_off(),
imported_unit_child_off()
{}
/// Constructor of @ref the type imported_unit_point.
///
/// @param import_off the offset of the point at which the unit has
/// been imported.
///
/// @param imported_die the die of the unit that has been imported.
imported_unit_point (Dwarf_Off import_off,
const Dwarf_Die& imported_die)
: offset_of_import(import_off),
imported_unit_die_off(dwarf_dieoffset
(const_cast<Dwarf_Die*>(&imported_die))),
imported_unit_cu_off(),
imported_unit_child_off()
{
Dwarf_Die imported_unit_child;
dwarf_child(const_cast<Dwarf_Die*>(&imported_die),
&imported_unit_child);
imported_unit_child_off =
dwarf_dieoffset(const_cast<Dwarf_Die*>(&imported_unit_child));
Dwarf_Die cu_die_memory;
Dwarf_Die *cu_die;
cu_die = dwarf_diecu(const_cast<Dwarf_Die*>(&imported_unit_child),
&cu_die_memory, 0, 0);
imported_unit_cu_off = dwarf_dieoffset(cu_die);
}
}; // struct imported_unit_point
/// "Less than" operator for instances of @ref imported_unit_point
/// type.
///
/// @param the left hand side operand of the "Less than" operator.
///
/// @param the right hand side operand of the "Less than" operator.
///
/// @return true iff @p l is less than @p r.
static bool
operator<(const imported_unit_point& l, const imported_unit_point& r)
{return l.offset_of_import < r.offset_of_import;}
/// Convenience typedef for a vector of @ref imported_unit_point.
typedef vector<imported_unit_point> imported_unit_points_type;
/// Convenience typedef for a vector of @ref imported_unit_point.
typedef unordered_map<Dwarf_Off, imported_unit_points_type>
tu_die_imported_unit_points_map_type;
static bool
find_symbol_table_section(Elf* elf_handle, Elf_Scn*& section);
@ -151,6 +233,11 @@ maybe_canonicalize_type(Dwarf_Off die_offset,
static int
get_default_array_lower_bound(translation_unit::language l);
static bool
find_lower_bound_in_imported_unit_points(const imported_unit_points_type&,
Dwarf_Off,
imported_unit_points_type::const_iterator&);
/// Convert an elf symbol type (given by the ELF{32,64}_ST_TYPE
/// macros) into an elf_symbol::type value.
///
@ -1769,6 +1856,7 @@ class read_context
translation_unit_sptr cur_tu_;
scope_stack_type scope_stack_;
offset_offset_map die_parent_map_;
tu_die_imported_unit_points_map_type tu_die_imported_unit_points_map_;
// A DIE -> parent map for DIEs coming from the alternate debug info
// file.
offset_offset_map alternate_die_parent_map_;
@ -2633,6 +2721,22 @@ public:
die_tu_map()
{return die_tu_map_;}
/// Getter for the map that associates a translation unit DIE to the
/// vector of imported unit points that it contains.
///
/// @return the map.
tu_die_imported_unit_points_map_type&
tu_die_imported_unit_points_map()
{return tu_die_imported_unit_points_map_;}
/// Getter for the map that associates a translation unit DIE to the
/// vector of imported unit points that it contains.
///
/// @return the map.
const tu_die_imported_unit_points_map_type&
tu_die_imported_unit_points_map() const
{return tu_die_imported_unit_points_map_;}
const corpus_sptr
current_corpus() const
{return cur_corpus_;}
@ -4185,6 +4289,43 @@ die_die_attribute(Dwarf_Die* die, bool die_is_in_alt_di,
return r;
}
/// Get the value of an attribute which value is supposed to be a
/// reference to a DIE.
///
/// @param die the DIE to read the value from.
///
/// @param attr_name the DW_AT_* attribute name to read.
///
/// @param result the DIE resulting from reading the attribute value.
/// This is set iff the function returns true.
///
/// @param look_thru_abstract_origin if yes, the function looks
/// through the possible DW_AT_abstract_origin attribute all the way
/// down to the initial DIE that is cloned and look on that DIE to see
/// if it has the @p attr_name attribute.
///
/// @return true if the DIE @p die contains an attribute named @p
/// attr_name that is a DIE reference, false otherwise.
static bool
die_die_attribute(Dwarf_Die* die, unsigned attr_name, Dwarf_Die& result,
bool look_thru_abstract_origin = true)
{
Dwarf_Attribute attr;
if (look_thru_abstract_origin)
{
if (!dwarf_attr_integrate(die, attr_name, &attr))
return false;
}
else
{
if (!dwarf_attr(die, attr_name, &attr))
return false;
}
bool r = dwarf_formref_die(&attr, &result);
return r;
}
/// Read and return a DW_FORM_addr attribute from a given DIE.
///
/// @param die the DIE to consider.
@ -5606,15 +5747,22 @@ die_virtual_function_index(Dwarf_Die* die,
/// die -> parent map to record the child -> parent relationship that
/// exists between the child and the given die.
///
/// The function also builds the vector of places where units are
/// imported.
///
/// This is done recursively as for each child DIE, this function
/// walks its children as well.
///
/// @param die the DIE whose children to walk recursively.
///
/// @param die_parent_map the die -> parent map to populate.
///
/// @param a vector containing all the offsets of the points where
/// unit have been imported, under @p die.
static void
build_die_parent_relations_under(Dwarf_Die* die,
offset_offset_map& die_parent_map)
offset_offset_map& die_parent_map,
imported_unit_points_type & imported_units)
{
if (!die)
return;
@ -5626,58 +5774,18 @@ build_die_parent_relations_under(Dwarf_Die* die,
do
{
die_parent_map[dwarf_dieoffset(&child)] = dwarf_dieoffset(die);
build_die_parent_relations_under(&child, die_parent_map);
if (dwarf_tag(&child) == DW_TAG_imported_unit)
{
Dwarf_Die imported_unit;
if (die_die_attribute(&child, DW_AT_import, imported_unit))
imported_units.push_back
(imported_unit_point(dwarf_dieoffset(&child),
imported_unit));
}
build_die_parent_relations_under(&child, die_parent_map, imported_units);
}
while (dwarf_siblingof(&child, &child) == 0);
}
/// Walk the DIEs under a given die and for each child, populate the
/// read_context::die_parent_map() to record the child -> parent
/// relationship that exists between the child and the given die.
///
/// This is done recursively as for each child DIE, this function
/// walks its children as well.
///
/// @param ctxt the read context to consider.
///
/// @param die the DIE whose children to walk recursively.
static void
build_primary_die_parent_relations_under(read_context& ctxt, Dwarf_Die *die)
{build_die_parent_relations_under(die, ctxt.die_parent_map());}
/// Walk the DIEs under a given die and for each child, populate the
/// read_context::alternate_die_parent_map() to record the child ->
/// parent relationship that exists between the child and the given
/// die.
///
/// This is done recursively as for each child DIE, this function
/// walks its children as well.
///
/// @param ctxt the read context to consider.
///
/// @param die the DIE whose children to walk recursively.
static void
build_alternate_die_parent_relations_under(read_context& ctxt, Dwarf_Die *die)
{build_die_parent_relations_under(die, ctxt.alternate_die_parent_map());}
/// Walk the DIEs under a given die and for each childde, populate the
/// appropriate die -> parent map to record the child -> parent
/// relationship that exists between the child and the given DIE.
///
/// @param ctxt the read context to use.
///
/// @param die the DIEs whose children to walk recursively.
///
/// @param die_is_from_alt_debug_info true if @p die is from the
/// alternate debug info section, false otherwise.
static void
build_die_parent_relations_under(read_context& ctxt, Dwarf_Die *die,
bool die_is_from_alt_debug_info)
{
if (die_is_from_alt_debug_info)
build_alternate_die_parent_relations_under(ctxt, die);
else
build_primary_die_parent_relations_under(ctxt, die);
}
/// Walk all the DIEs accessible in the debug info (and in the
@ -5702,8 +5810,13 @@ build_die_parent_maps(read_context& ctxt)
Dwarf_Die cu;
if (!dwarf_offdie(ctxt.alt_dwarf(), die_offset, &cu))
continue;
build_die_parent_relations_under(ctxt, &cu,
/*die_is_from_alt_debug_info=*/true);
ctxt.cur_tu_die(&cu);
imported_unit_points_type& imported_units =
ctxt.tu_die_imported_unit_points_map()[die_offset] =
imported_unit_points_type();
build_die_parent_relations_under(&cu,
ctxt.alternate_die_parent_map(),
imported_units);
}
address_size = 0;
@ -5717,111 +5830,112 @@ build_die_parent_maps(read_context& ctxt)
Dwarf_Die cu;
if (!dwarf_offdie(ctxt.dwarf(), die_offset, &cu))
continue;
build_die_parent_relations_under(ctxt, &cu,
/*die_is_from_alt_debug_info=*/false);
ctxt.cur_tu_die(&cu);
imported_unit_points_type& imported_units =
ctxt.tu_die_imported_unit_points_map()[die_offset] =
imported_unit_points_type();
build_die_parent_relations_under(&cu,
ctxt.die_parent_map(),
imported_units);
}
}
/// Get the last point where a DW_AT_import DIE is used to import a
/// given (unit) DIE, before a given DIE is found. That given DIE is
/// called the limit DIE.
///
/// Said otherwise, this function returns the last import point of a
/// unit, before a limit.
/// Get the point where a DW_AT_import DIE is used to import a given
/// (unit) DIE, between two DIEs.
///
/// @param ctxt the dwarf reading context to consider.
///
/// @param partial_unit_offset the imported unit for which we want to
/// know the insertion point of. This is usually a partial unit (with
/// know the insertion point. This is usually a partial unit (with
/// tag DW_TAG_partial_unit) but it does not necessarily have to be
/// so.
///
/// @param parent_die the DIE under which the lookup is to be
/// performed. The children of this DIE are visited in a depth-first
/// manner, looking for the die which is at offset @p
/// partial_unit_offset.
/// @param first_die_offset the offset of the DIE from which this
/// function starts looking for the import point of
/// @partial_unit_offset. Note that this offset is excluded from the
/// set of potential solutions.
///
/// @param die_offset the offset of the limit DIE.
/// @param first_die_cu_offset the offset of the (compilation) unit
/// that @p first_die_cu_offset belongs to.
///
/// @param imported_point_offset. The resulting imported_point_offset.
/// Note that if the imported DIE @p partial_unit_offset is not found
/// before @p die_offset, this is set to the last @p
/// partial_unit_offset found under @p parent_die.
/// @param last_die_offset the offset of the last DIE of the up to
/// which this function looks for the import point of @p
/// partial_unit_offset. Note that this offset is excluded from the
/// set of potential solutions.
///
/// @return true iff an imported unit is found before @p die_offset.
/// Note that if an imported unit is found after @p die_offset then @p
/// imported_point_offset is set and the function return false.
/// @param imported_point_offset. The resulting
/// imported_point_offset. Note that if the imported DIE @p
/// partial_unit_offset is not found between @p first_die_offset and
/// @p last_die_offset, this parameter is left untouched by this
/// function.
///
/// @return true iff an imported unit is found between @p
/// first_die_offset and @p last_die_offset.
static bool
find_last_import_unit_point_before_die(read_context& ctxt,
find_import_unit_point_between_dies(read_context& ctxt,
size_t partial_unit_offset,
const Dwarf_Die* parent_die,
size_t die_offset,
Dwarf_Off first_die_offset,
Dwarf_Off first_die_cu_offset,
size_t last_die_offset,
size_t& imported_point_offset)
{
if (!parent_die)
return false;
tu_die_imported_unit_points_map_type::iterator iter =
ctxt.tu_die_imported_unit_points_map().find(first_die_cu_offset);
assert(iter != ctxt.tu_die_imported_unit_points_map().end());
Dwarf_Die child;
if (dwarf_child(const_cast<Dwarf_Die*>(parent_die), &child) != 0)
return false;
imported_unit_points_type& imported_unit_points = iter->second;
imported_unit_points_type::const_iterator b = imported_unit_points.begin();
imported_unit_points_type::const_iterator e = imported_unit_points.end();
// This list contains the children of 'parent_die' in reversed
// topological order, starting from the DIE of 'die_offset'; that
// die_offset itself is excluded. If the children of parent_die
// don't contain the DIE of 'die_offset', then the list contains all
// the children of 'parent_die'.
std::list<size_t> imported_unit_die_offsets;
do
{
if (dwarf_dieoffset(&child) == die_offset)
break;
if (dwarf_tag(&child) == DW_TAG_imported_unit)
imported_unit_die_offsets.push_front(dwarf_dieoffset(&child));
}
while (dwarf_siblingof(&child, &child) == 0);
find_lower_bound_in_imported_unit_points(imported_unit_points,
first_die_offset,
b);
// Look if one of the children of 'parent_die' is the import point
// we are looking for, starting from the last child of 'parent_die'.
for (std::list<size_t>::iterator i = imported_unit_die_offsets.begin();
i != imported_unit_die_offsets.end();
++i)
{
Dwarf_Die die_memory, *die;
die = dwarf_offdie(ctxt.dwarf(), *i, &die_memory);
if (last_die_offset != static_cast<size_t>(-1))
find_lower_bound_in_imported_unit_points(imported_unit_points,
last_die_offset,
e);
Dwarf_Die imported_unit;
bool is_in_alt_di = false;
if (die_die_attribute(die, /*die_is_in_alt_di=*/false,
DW_AT_import, imported_unit, is_in_alt_di))
if (e != imported_unit_points.end())
{
if (partial_unit_offset == dwarf_dieoffset(&imported_unit))
for (imported_unit_points_type::const_iterator i = e; i >= b; --i)
if (i->imported_unit_die_off == partial_unit_offset)
{
imported_point_offset = dwarf_dieoffset(&child);
imported_point_offset = i->offset_of_import ;
return true;
}
}
}
// Look if the descendants of the children of 'parent_die' contain
// the import point we are looking for, starting from the last child
// of 'parent_die'.
for (std::list<size_t>::iterator i = imported_unit_die_offsets.begin();
i != imported_unit_die_offsets.end();
++i)
for (imported_unit_points_type::const_iterator i = e; i >= b; --i)
{
Dwarf_Die die_memory, *die;
die = dwarf_offdie(ctxt.dwarf(), *i, &die_memory);
Dwarf_Die imported_unit;
bool is_in_alt_di = false;
if (die_die_attribute(die, /*die_is_in_alt_di=*/false,
DW_AT_import, imported_unit, is_in_alt_di))
if (find_last_import_unit_point_before_die(ctxt,
if (find_import_unit_point_between_dies(ctxt,
partial_unit_offset,
&imported_unit,
die_offset,
i->imported_unit_child_off,
i->imported_unit_cu_off,
(Dwarf_Off)-1,
imported_point_offset))
return true;
}
}
else
{
for (imported_unit_points_type::const_iterator i = b; i != e; ++i)
if (i->imported_unit_die_off == partial_unit_offset)
{
imported_point_offset = i->offset_of_import ;
return true;
}
for (imported_unit_points_type::const_iterator i = b; i != e; ++i)
{
if (find_import_unit_point_between_dies(ctxt,
partial_unit_offset,
i->imported_unit_child_off,
i->imported_unit_cu_off,
(Dwarf_Off)-1,
imported_point_offset))
return true;
}
}
return false;
}
@ -5851,14 +5965,28 @@ find_last_import_unit_point_before_die(read_context& ctxt,
/// Note that if an imported unit is found after @p die_offset then @p
/// imported_point_offset is set and the function return false.
static bool
find_last_import_unit_point_before_die(read_context& ctxt,
find_import_unit_point_before_die(read_context& ctxt,
size_t partial_unit_offset,
size_t where_offset,
size_t& imported_point_offset)
{
size_t import_point_offset = 0;
if (find_last_import_unit_point_before_die(ctxt, partial_unit_offset,
ctxt.cur_tu_die(), where_offset,
Dwarf_Die first_die_of_tu;
if (dwarf_child(const_cast<Dwarf_Die*>(ctxt.cur_tu_die()),
&first_die_of_tu) != 0)
return false;
Dwarf_Die cu_die_memory;
Dwarf_Die *cu_die;
cu_die = dwarf_diecu(const_cast<Dwarf_Die*>(&first_die_of_tu),
&cu_die_memory, 0, 0);
if (find_import_unit_point_between_dies(ctxt, partial_unit_offset,
dwarf_dieoffset(&first_die_of_tu),
dwarf_dieoffset(cu_die),
where_offset,
import_point_offset))
{
imported_point_offset = import_point_offset;
@ -5924,12 +6052,12 @@ get_parent_die(read_context& ctxt,
assert(where_offset);
size_t import_point_offset = 0;
bool found =
find_last_import_unit_point_before_die(ctxt,
find_import_unit_point_before_die(ctxt,
dwarf_dieoffset(&parent_die),
where_offset,
import_point_offset);
if (!found && die_is_from_alt_di)
;
abort();
else
{
assert(found);
@ -6193,6 +6321,39 @@ get_default_array_lower_bound(translation_unit::language l)
return value;
}
/// For a given offset, find the lower bound of a sorted vector of
/// imported unit point offset.
///
/// The lower bound is the smallest point (the point with the smallest
/// offset) which is the greater than a given offset.
///
/// @param imported_unit_points_type the sorted vector of imported
/// unit points.
///
/// @param val the offset to consider when looking for the lower
/// bound.
///
/// @param r an iterator to the lower bound found. This parameter is
/// set iff the function returns true.
///
/// @return true iff the lower bound has been found.
static bool
find_lower_bound_in_imported_unit_points(const imported_unit_points_type& p,
Dwarf_Off val,
imported_unit_points_type::const_iterator& r)
{
imported_unit_point v(val);
imported_unit_points_type::const_iterator result =
std::lower_bound(p.begin(), p.end(), v);
bool is_ok = result != p.end();
if (is_ok)
r = result;
return is_ok;
}
/// Given a DW_TAG_compile_unit, build and return the corresponding
/// abigail::translation_unit ir node. Note that this function
/// recursively reads the children dies of the current DIE and